Reef Ramblings

Keep it Balanced.

One of the most import considerations when it comes to maintaining calcium and carbonate levels in the reef aquarium is, that whatever method is used, it must be a balanced one. Corals need calcium and carbonates to be available in a particular ratio in order to build a healthy calcium carbonate skeleton. If this balance is not maintained the consequences can present themselves as a difficulties in maintaining pH, calcium, and carbonate levels. For a supplementation to be described as balanced it needs to be providing something in the region of 20 ppm calcium along with 2.8 dKH (1meq/l) carbonates.

Many of you of course will be familiar with liquid supplements for calcium dosing but probably think of them as being pretty basic stuff only suitable for beginners. In fact liquid supplements for maintaining calcium and carbonates can be very sophisticated products, superior in some ways to the more technical solution offered by calcium reactors.

Although there are plenty of different supplements for both calcium and carbonates on the market, many of these are unsophisticated products that will replenish calcium or carbonates but with long term use result in ionically unbalanced water. This can be particularly dangerous if water changes aren’t carried out on a regular basis. With no water changes, levels of sodium and chloride from these supplements can build up producing water that’s more like a solution of table salt than seawater!

There are three types of liquid calcium supplements of real interest to us, these are the ionically balanced two part supplements, the Balling Method, and what I would describe as hybrid systems which seem to combine elements of the first two. The theory behind all of these methods is fairly similar as they all aim to add calcium and carbonates in a balanced manner, the differences tend to be in terms of how associated ions, minor and trace elements are included into the dosing regime.

When using any of these systems I’d advise keeping a watch on the salinity of your reef as one side effect of these various methods can be an increase in salinity. With use it will soon be apparent how much the salinity is shifting and you can then work out a simple solution to correcting the problem, for example every so many days or weeks removing a given volume of water from the aquarium and replacing it with fresh RO.

Balling Method

This system of calcium replenishment was originated by Hans-Werner Balling and first published in 1994. Essentially the system consists of dosing calcium chloride and sodium bicarbonate as separate solutions in a strict ratio but as the chloride and sodium ions are not used in the aquarium, a third additive is required to balance out what would otherwise produce an increase in salinity. This third solution added to the aquarium is, in effect, a sodium chloride free sea salt mix that brings with it many minor and trace elements.

Balling Light

A comparatively recent introduction, a kind of ‘lazy reefkeepers’ version of the the Balling Method that dispenses with the use of sodium chloride free sea salt mixture and relies instead on regular water changes to control salinity increases.

See; EcoBalling Method.

Two Part Balanced Ionic Supplements

These two part systems are designed to add calcium and carbonate, along with their associated ions in a manner mimicking the natural ionic ratios of seawater.  The calcium component will include some or all of the following ions (depending on manufacturer): bromide, calcium, cesium, chloride, chromium, cobalt, copper, iron, lithium, magnesium, manganese, nickel, rubidium, strontium, zinc. While the carbonate component will include some or all of the following ions (depending on manufacturer) bicarbonate, borate, carbonate, fluoride, iodide, molybdate, potassium, sodium, selenate, tungstate, vanadate. Overtime you’ll register a slight increase in salinity as, in a sense, it’s almost like dosing with a concentrated sea salt mix.

Hybrid Systems

A number of manufacturers produce what I’d describe as hybrid systems, they’re not Balling Method and neither are they strictly a two part solution.
They tend to consists of three to five parts parts – two of them being a two part calcium/carbonate additive with the additional parts being various trace element mixtures which, like the calcium and carbonate additives, need to be dosed separately.

Better Than a Calcium reactor?

Well yes and no.
Liquid dosing doesn’t introduce any phosphate into your reef system, whereas a calcium reactor, depending on the quality of the media being used, can be the source of unwanted levels of phosphate.
Liquid dosing won’t alter your pH, although it may help support it, however a poorly set up calcium reactor can easily lower the pH of your reef.
Liquid dosing can often be an almost complete source of supply of minor elements and trace elements.
Liquid dosing will contribute far more available calcium than calcium hydroxide (kalkwasser).
For covered aquariums where there’s not enough evaporation to allow kalkwasser dosing or for reef tanks where there’s no sump space to allow for a CO2 reactor, liquid dosing can be the best solution to calcium replenishment.
Knowing the calcium demand of you reef you can easily calculate the required dosage from the manufacturers product information; usually the manufacturer will tell you how many mg/l calcium is provide for a give dose. Getting the dosage right with a calcium reactor can involve making a lot of adjustments to flow rates at the same time as performing a lot of calcium and carbonate testing before determining the correct settings for your reef.
Manual liquid dosing can be a more economical solution for smaller reefs, or reefs with a lower calcium demand where a calcium reactor might seem to represent expensive overkill. As the size of the reef system or the calcium demand of the corals increases the cost of the supplements used for liquid dosing can become high compared to the running costs of a calcium reactor (replacement media and CO2).
Calcium reactors are expensive items of equipment to purchase but the running costs are low.
Both forms of calcium reactor, kalkwasser reactor and CO2 reactor, can constitute very real dangers to your reef if they go wrong and are also potentially dangerous to you the aquarist. Calcium hydroxide is a very caustic powder that should be handled carefully and kept away from children and pets. Carbon Dioxide (CO2) is kept in pressurised cylinders which if mishandled may explode.

Ultimately the answer may lay with combining the two methods to get the best from each.

How to dose manually.

Some manufacturers may suggest leaving a minimum time between dosing the separate parts (say 20 minutes apart), whereas others may just say to dose the separate parts into a high flow area of the aquarium.
Always follow the manufacturers guidelines. Though, having said that, when instructions are given for weekly dosing there are benefits to be had if you pro rata the recommendation to a daily dose.

Automatic dosing.

Automatic dosing involves the additional cost of purchasing dosing pumps but brings with it a number of advantages.
Once your dosing regime is set up or programmed you can forget about the hassles of having to remember when to dose and with how much. Maintenance becomes a matter of replenishing each part of your supplement as they become exhausted. Depending on the demand of your reef and the volume of the containers holding the individual solutions you can go some time with out having to pay attention to calcium dosing. Nevertheless, I’d recommend checking calcium and carbonate levels each time you restock. There are two reasons for periodically measuring calcium and carbonate levels. Firstly, to ensure you’ve accurately calculated out the correct dosage and that the pumps are operating as desired. Secondly, now you’re making appropriate quantities of calcium and carbonates available at a near constant level, you’ll most likely find that as your corals benefit from this, that they’ll grow and hence the demand will increase.

Liquid supplements can be easily added to the aquarium automatically by using dosing pumps. This is usually done by the use of peristaltic pumps.
These pumps consist of a casing, a rotor, and a length of special hose. The rotor has two or more short arms ending in rollers, as it rotates these rollers squeeze the hose against the housing in turn, as each roller squeezes the hose it pushes a small volume of liquid along the length of the hose and through the pump. More expensive pumps can be programmable, while cheaper, non-programmable pumps can be controlled by using an aquarium computer system. Most domestic timers will be unsuitable for this application unless they’re capable of switching dosing pumps on and off for timed periods of a minute or less.
A separate container is required for each different component being dosed; the pump then draws the solution from the container, through the pump, and feeds it into the aquarium. This is all done through 6mm diameter airline tubing and it’s usual to employ an airline check valve somewhere along the line to ensure efficient delivery. Depending on the make of your programmable pump you can alter how may times a day it’ll dose and how long it’ll dose for.  Most of these pumps have a fixed dosing rate so it’s the length of time the pump is working throughout the day that’ll control the volume of liquid dosed. If the pump has a dosing rate of 3l/hr and we want to add 50ml a day that represents a running time of only one minute, so it may well pay to dilute the liquid with RO water to allow repeated dosing throughout the day.
The various feeds from the doser should be delivered into a high flow area and, if the pumping system is going to deliver more than one component at a time, should be spaced apart accordingly. Perhaps a minimum spacing of 10 cm between dosing locations.

Hints and Tips.

Most importantly, remember to never mix the calcium and carbonate components of any of these multi-part liquid supplements together in a container prior to dosing. You’ll just end up with calcium carbonate in a form that’s not accessible to your corals.
If it appears to start “snowing” in the tank after the addition of the calcium and carbonate liquids this means calcium carbonate is being precipitated out of solution. You need to either dose further apart or into a higher flow area of the tank. It may also be worth double-checking your calcium levels to make sure you’re not in a state of calcium supersaturation.
Before starting to dose with a balanced liquid supplement it’s advisable to ensure that your calcium and carbonate levels are at, or near, to the correct levels for a reef tank. Somewhere in the range of say, 380 – 440 ppm calcium 7 – 11 dKH.
If you’re dosing automatically, using peristaltic pumps, then I’d recommend that you break up the daily dosage into a number of smaller doses to be administered throughout the day. This way you can minimise fluctuations in the calcium levels and offer a steadier environment, reflecting the constant levels found on the reef in the wild.

Correcting Calcium and Carbonate Levels.

Your calcium and carbonate levels can be out of balance in a number of different ways, each requiring a slightly different method of correction.

1. Calcium and carbonates too high: – discontinue all forms of supplementation and wait for the levels to naturally decrease. Monitor regularly.
2. Calcium and carbonates too low: – add balance liquid supplements at a slightly higher dosage than recommended. Monitor until acceptable levels are reached and then cut back on dosage until maintenance of required levels is achieved.
3. Calcium too high, carbonates too low: – add carbonate component only. Monitor both parameters until back in target range.
4. Calcium too low, carbonates too high: – add calcium component only. Monitor both parameters until back in target range.
5. Calcium at target level, carbonates too low: – add calcium component at lower dosage, say 50% and add carbonate component at double dosage (don’t exceed manufacturers’ recommended maximum dose). Monitor both parameters until back in target range.
6. Calcium too low, carbonates at target level: – add carbonate component at lower dosage, say 50% and add calcium component at double dosage (don’t exceed manufacturers’ recommended maximum dose). Monitor both parameters until back in target range.

How to Calculate Dosage for Automatic Dosing.

If the peristaltic pump you’re using has a typical dosing rate of 3l/hr that equates to 3000ml/hr or 50ml/min. To find how long you’d need to run this pump to dose a given quantity, divide the required dose in ml by the dosing rate.
Example 1: if you want to add 50ml a day, divide 50 by 50, this gives you a figure of 1 representing a running time of one minute.
Example 2:  if you want to add 25ml a day, divide 25 by 50, this gives you a figure of 0.5 representing a running time of half a minute or 30seconds.
As you can see we are dealing with small dosages and short time periods, so it can pay to dilute the liquid with RO water to allow repeated dosing throughout the day. Take any dilution into account when calculating out your daily dosage.
Example 3: if you take the dosage from example I above and dilute it 1:1 (50ml RO + 50ml supplement) you’d then need to dose 100ml per day, doubling the pump run time to 2 minutes to deliver the required amount of supplement. This extended running time can then be spread over the course of the day by breaking the dosing down to 1 minute twice a day, 30 seconds four times a day, or 15 seconds eight times a day.
Example 4: example 2 above would really benefit from dilution. By diluting 3:1 (75ml RO + 25ml supplement) you could then dose the same number of times as in example 3.

Tim Hayes
Midland Reefs
©2009 – 2011

So how about this for a unique reef aquarium related crime? It’s been recently reported that 300,000 US pounds of maricultured live rock (that’s 135 UK tons or 136,000 kgs!) has been stolen in the Florida Keys.

Sometime during the past 18 months someone stole about 300,000 pounds of decorative live rock that Miami boat captain Neal Novak had planned to harvest for salt-water and reef aquariums from his aqua farm three miles offshore of Islamorada. A spokesman for the Florida Fish & Wildlife Conservation Commission said, ”As far as I know, this is a first in the Keys, we’ve caught people bringing in live rock, but not stealing from someone’s aqua farm.”

Novak started his live rock harvesting company in 2005. It took six months for him to obtain a federal permit from the National Oceanic and Atmospheric Administration for a one-acre leased aqua farm and a further 2 ½ years to place the rock in 20 feet of water. The rock used was a high quality Florida aquifer rock of light yellow, white or brown colour looking like Swiss cheese, from a Homestead quarry. After three to five years in the clear, mostly nutrient-free water off Islamorada, the rocks turn purple and can be considered as live rock, having become colonised by coralline algae, feather duster worms, sponges, and many other kinds aquatic organisms.
Live rock produced this way sells for about $3 per pound wholesale and $8 per pound retail, making his loss somewhere between 1 to 2 million dollars, this doesn’t include Novak’s investment in the equipment need to run the business. He’d bought a flatbed truck to transport the rock, a special boat designed to hold the large amount of weight that also contained two salt water holding tanks for transporting the harvested live rock, and five tanks totalling a capacity of 1,400 gallons for holding the live rock ready for sale to pet stores and other aquarium suppliers.

The theft was discovered on May 13 when he and his wife made trip out to the aqua farm to begin the harvest. Novak said he never thought anyone would steal 150 tons of submerged rock in an area used by recreational divers near about seven other aqua farms. The rocks were not insured. ”About 30 to 50,000 pounds were left, basically just rubble left on the sand” he said “That’s all I have left of five years of work. It’s financially ruined me.” The last time he’d checked on the aqua farm was about 1 ½ years ago, when he took a sample. ”I should have checked on them more, but I had to care for my parents,”.

The Monroe County Sheriff’s Office is investigating along with FWC. The crime is grand larceny of farm animal aquaculture species, a third-degree felony. If anyone reading this out in Florida has any information about the theft, please help Neal Novak out and get in touch with the Sheriff’s Office.

Tim Hayes
Midland Reefs
©2009

MarinePure (previously known as ReefresH2O) – The Natural Choice for Fish Hobbyists.

Here are a few of the testimonials we’ve been receiving about MarinePure media. The first couple are from the US where this media has been around for a while longer than in the UK and EU.

“I currently maintain five 55-gallon tanks of Hawaiian fish, and in some of them MarinePure is the only method of filtration I use,” said John Dawe, fish hobbyist and past president of both the Marinelife Aquarium Society of Michigan (MASM) and Midwest Marine Conference, as well as a MarinePure customer for close to 10 years.

“MarinePure is exceptionally reliable, and so convenient to use as an almost instant biofiltration system.  I can literally take a conditioned piece from an existing tank and put it directly into a new tank of quarantined fish, or get a new piece of media ready in just a couple of days by seasoning it in an existing tank,” Dawe explained.  “I wouldn’t use any other biofiltration product.”

“As a long-time hobbyist who has also been in the coral propagation business, effective and reliable media for both filtration and coral growth is important from many aspects,” said Rick Smith, aquatic enthusiast and former fish and coral frag wholesaler.  “MarinePure is the closest product available to reef rock, offering exceptionally high porosity and making it much easier to bore propagation holes than when using concrete-based media.  Offering a neutral substrate with an ability to rapidly absorb up to 30 percent of their weight in micronutrient-rich salt water, MarinePure coral frag plugs promote instant coral adhesion and long-term, healthy growth.”“I’ve been using this product line for about a decade now, and currently maintain a 92-gallon reef tank that exclusively employs MarinePure biofiltration media.  With no need for water changes in more than three years, the tank is full of healthy, thriving corals thanks to MarinePure.”

In the short time that MarinePure products have been available in the UK they’ve proved an unqualified success in the shops where they’ve been tried out, particularly in the marine sector. Retailers using MarinePure products in their shop systems report unprecedented low nitrate levels.

Richard Sendel, owner of Tropical Paradise, Eastleigh, near Southampton placed four MarinePure Blocks in the sump of his 4,500 litre shop fish system which at the time was running at 100 ppm Nitrate, mainly because Richard makes sure his fishes get properly fed 3 times a day. Now, after 10 weeks, Richard is reporting an unprecedented Nitrate level of 2 ppm!

Steve Unwin of Mastin Moor Aquatics is using the Blocks in his fish system; Steve made the additional observation that since installing the blocks in the system, water parameters have become much more stable rather than fluctuating as the fish load varies over the course of the week (as fishes are sold and the system restocked).

Malc, proprietor of Aquatics World, Coventry, using a combination of  Spheres in a large trickle tower along with Blocks in the system, is finding negligible levels of Nitrate in his fish system.

From Switzerland Sascha Sonderegger of Nightsun Aquaristics emailed saying, “I tried a MarinePure block in my live rock tank and the result now is really good. I put it in to the tank on the 17th December with a nitrate around 100mg/l. When I put in new live rock, normally the NO3 will go up a little, this time the NO3 was 25mg/l after 10 days.”
We’ve had plenty more reports from aquarists, both retailers and hobbyists, having great success in reducing and controlling the nitrate levels within their systems. If you’ve got a MarinePure success story that you’d like to share, email me at tim@midlandreefs.co.uk or give me a call on 01543 685599, and I’ll publish your story here.

Tim Hayes
Midland Reefs
©2009 – 11

Water testing in the reef aquarium.

With more than twenty different physical and chemical parameters available for testing in the reef aquarium you may be forgiven if you find the whole subject of water testing a little confusing.

Why do you need to test?

No matter what anyone, no matter how experienced, says, you can’t tell what’s going on in an aquarium just by looking. You need you employ a variety of methods to find out what’s going on in your reef.

Which tests should you carry out?

Broadly speaking you can divide the available tests into three categories: the every day parameters that need to be adhered to, parameters you may need to examine in the case of a problem, and parameters that could perhaps be described as aspirational, ones that might be looked at when trying to optimise an already successful reef.

The essential parameters that need to be monitored in an established reef are: Temperature, Salinity, pH, Calcium and Carbonates, Nitrate, and Phosphate.
With newly set up reefs you’ll additionally need to pay attention to Ammonia and Nitrite and, although calcium and carbonates are of less importance until corals are introduced, proliferation of coralline or calcareous algae can make significant demands of these two parameters.

How do you test?

Depending on parameter we can choose from chemical based tests, electrical probes, photoelectrical sensors, optical instruments, traditional thermometers, and hydrometers. Chemical tests tend to be used for chemical parameters; physical parameters may be measured by a variety of other means.

What can’t we test for?

Given the budget, or access to an extremely well equipped laboratory, there’s not a lot that can’t be measured. But for the average reefkeeper (plus the majority of public aquariums) there’re plenty of things that can’t be quantified, for example the majority of the seventy-odd trace elements that are found in saltwater cannot be readily measured and, even if they could, there may be little merit as these elements, by definition, are available in trace or minute amounts. Their concentrations will be maintained by a combination of regular water changes and the food introduced into the aquarium. Indeed, given the speculation about the accumulation of trace elements in the reef aquarium, the value of water changes is that they can also help dilute any such accumulation.

The more important factors that we can’t test for are biological or biological in origin.
We can’t test for chemicals released into the water as a part of the non-stop chemical war being waged in our reefs by corals and other invertebrates.
We can’t test for the biological oxygen demand (BOD) of our reefs outside of the laboratory. This is the total oxygen demand of all the creatures present in our reefs.

At what levels should the various parameters be maintained?

This is a tricky one. You can aim to replicate natural seawater levels or you can opt for levels that have evolved over the lifetime of the hobby. In reference books you’ll often find discrepancies regarding natural sea water parameters, although the sea can largely be considered stable there are variations. Variations in salinity, temperature, and calcium are widespread, changing with depth, season, atmospheric pressure, and proximity to land. Locally these can change over the course of the year. We are primarily concerned with seawater from tropical latitudes in the vicinity of coral reefs so the figures I’ve quoted reflect this. See: Reef Ramblings – Recommended Reef Tank Parameters.

Temperature.

Measured by traditional thermometer, stick-on external thermometer, or electronic probe.

A reef needs to be maintained at a stable temperature within a fairly narrow range. Water temperature in a reef tends to edge towards the high end owing to the amount of lighting used and, in recent years, there has been a tendency towards a higher than reef safe ambient temperature for a few weeks of the year during the summer months.
Generally reef aquaria should be maintained somewhere between a minimum of 21˚C and a maximum of around 28˚C. For most captive reefs a temperature in the region of 24 – 25˚C, plus or minus one degree, will work well.
Note: some aquarium writers, myself included, advocate slightly higher, more natural temperatures in line with actual reef temperatures (up to a maximum of 32˚C). Higher temperatures result in lower levels of oxygen saturation and increased metabolic rates, factors that need to be taken into account if you decide to go this route.

Dissolved oxygen.

Measured using chemical based test kit or electronic probe.

This is affected by temperature, flow rate, total animal load, and surface agitation. This is an extremely important parameter that’s rarely measured. In practise, a well-designed reef featuring good gas exchange through surface agitation, circulation, and aeration, that’s not overstocked, will most likely have adequate levels of dissolved oxygen. Saltwater holds lower levels of oxygen than freshwater and the higher the temperature the less oxygen available.

Salinity.

Modes of testing: Hydrometer. Electronic probe. Optical instrument (Refractometer)

As with temperature, this is another parameter critical to the survival of the animals in the captive reef.
Best tool for the job here is the refractometer as it gives a direct reading of salinity independent of temperature.
Hydrometers do not actually measure salinity they measure density in terms of specific gravity – it is important that if you’re using specific gravity that you always state the temperature of the sample as density varies with temperature.

Conductivity

Another method used to assess salinity. This uses a probe and meter and is more commonly used in aquaculture. Although accurate, may be misleading if water chemistry is awry, as this is actually a measurement of total dissolved solids and may be indicating the presence of ions other than sodium chloride.

pH

Measured using a chemical based test kit or electronic probe.

In simple terms this is a measure of the acidity or alkalinity of a solution. A pH of 7 is considered neutral, a number lower than this tells you a solution is acid, and a number higher tells you a solution is alkaline. The scale used is logarithmic so a pH of 8 is ten times more alkaline than a ph of 7, a pH of 9 one hundred times more alkaline. Electronic testing is far better than chemical test kits owing to the finer resolution offered.
Note: pH fluctuates over the course of twenty four hours in response to biological activity such as respiration and photosynthesis. Generally pH is lowest first thing in the morning before the lights go on, it rises over the course of the day, peaking at lights out in the evening. For this reason, always test at the same time of day so meaningful comparisons can be made.

Carbonates/Alkalinity.

Chemical based test kit. Measured in milliequivalents per litre (meq/L) or degrees hardness (dKH). 1 meq/L = 2.8 dKH.

This is the buffering capacity of seawater, its ability to maintain pH, resisting the trend towards acidification resulting from biological processes such as respiration. As alkalinity is a function of carbonates and bicarbonates, along with a few other compounds, it can also be used to evaluate the availability of carbon that, along with calcium, goes to providing the material for calcification in corals.

Calcium.

Modes of testing: chemical based test kit, electronic probe (accuracy and reliability not yet proven at hobby prices).

Calcium and carbonates should always be considered together. There is little point in testing one without the other and there is no point aiming for some particular value of Calcium without the Carbonates being balanced in the correct proportion required for calcification.

Magnesium.

Chemical based test kit.

Magnesium has an important role to play in the reef aquarium in supporting the buffering system and in its effects on the process of calcification. Magnesium should be about three times the level of Calcium in the reef so, for example, if Calcium were at 400 ppm you’d expect to see Magnesium at around 1200 ppm.

Nitrogen cycle.

Ammonia, Nitrite, Nitrate, and Nitrogen gas.

Monitoring the nitrogen cycle lets you evaluate how efficiently filtration is taking place. Both Ammonia and Nitrite are potentially lethal and should not be present in the aquarium. Once a reef is established there’s little to gain by testing these two parameters unless you are adding additional livestock or live rock, or if you’ve experienced the loss of a fish or other animal where you’ve been unable to recover the body.
In a newly set up reef monitoring Ammonia and Nitrite will allow you to judge when it’s safe to start adding livestock.

Ammonia.

Chemical based test kit.

When raising larval marine animals it can be useful to employ an Ammonia indicator badge, especially as a larval rearing rarely features filtration. Note: Ammonia toxicity increases with pH. It can be a good idea when running larval systems with no filtration to maintain a lower pH to take advantage of this, as toxicity can then be negligible. Don’t try this in a reef!

Nitrite.

Chemical based test kit.

Nitrate.

Chemical based test kit.

A well set up reef should show little if anything in the way of Nitrate. Although not toxic, as with Ammonia and Nitrite, it’s necessary to monitor Nitrate to ensure the level stays low to help prevent algal growth, at the same time if you’re getting a zero measurement, it may well indicate that a small amount of nitrate needs to be added for the well being of your corals.

Phosphate.

Chemical based test kit.

This is one parameter you certainly want to keep under control. In combination with elevated levels of Nitrate, Phosphate acts as fuel for unwanted algal growth. Additionally, raised levels of Phosphate inhibit calcification in stony corals.
When you use a good quality phosphate adsorbtion medium the only way you can tell if its capacity is exhausted is by regular testing for phosphate. If you reach a point where the level of phosphate is no longer being reduced, or, indeed is increasing, then that’s time to replace your phosphate remover with new.

Minor or Trace Elements.

Chemical based test kits.

Although there are test kits available for these, for some parameters the value of testing is questionable. Some test kits may either produce a result that is difficult to quantify or difficult to reproduce.
Testing of these parameters can be considered aspirational, as when you’re trying to fine-tune a reef to perfection (a questionable pastime) or, more usefully if you’re trying to perfect conditions for a particular difficult coral such as Goniopora species. In this example there’s been a certain amount of speculation regarding the importance of iron and Manganese in maintaining these corals.
These parameters may also come under scrutiny in a last ditch effort to sort out a particularly troubled reef when no other obvious causes can be found.

Boron

Boron is another element that contributes to the buffering system in saltwater. Salts that contain higher levels of Borate may give incorrect readings when standard Alkalinity test kits are used.

Iodine.

The jury is still out when it comes to the utility of adding Iodine to the reef aquarium. Some aquarium writers are against its addition, while others are in favour. Toxic if over dosed, it is important for the growth of many species of macro-algae and is found in the tissue of some soft corals. Iodine exists in a number of different forms in saltwater, which may be one reason that testing produces unreliable results.

Iron.

Given the low levels of Iron in seawater the prospect of testing for it in any meaningful way is slim. However iron is important for algae including zooxanthellae, the symbiotic algae associated with photosynthetic corals.

Silicon.

Silicates shouldn’t really be a problem these days. Before we adopted the practise of using RO water to make up fresh saltwater and for evaporation top up, it was quite common for aquaria to suffer a bloom of brown algae (actually diatoms) after every water change.
RO membranes aren’t as efficient at removing silicates as they are at removing some other elements, consequently special, more expensive membranes are available that remove a greater proportion. This may not be a good idea, silicates are required for the healthy growth of sponges and diatoms, as long as they don’t proliferate excessively, are a useful source of nutrition for many reef animals.

Strontium.

Strontium is another element that’s in dispute over its application in the reef aquarium. Anecdotal evidence seems to support the addition of Strontium, yet there’s some evidence that present day corals don’t utilise it in the same way a corals from the geological record, an oft cited source for the chemistry of calcification. Natural seawater levels should be fine but there is a question over the accuracy of test kits available in the hobby.

Copper.

Chemical based test kit.

Copper isn’t generally a test required for the reef aquarium. The reason for this test is to quantify levels of copper when it’s being used as a therapeutic for fish disease. Copper is toxic to marine invertebrates so can’t be used in the reef, if someone sells you some cheap rock to use in your reef that has previously been in a fish only tank, then I’d certainly suggest soaking the rock in for a week or so before testing whether it’s leaching copper from some previous cycle of medication.

Redox.

Electronic probe.

Redox or Oxygen Reduction Potential (ORP) may be monitored for a couple of different reasons. When using Ozone, a redox probe and controller can be used to control the amount of ozone being applied, and prevent dangerous overdosing from occurring.
A more general usage of an ORP monitor is as an indicator of the overall health of a reef system. Observing a downward trend in the reading alerts you to the fact that conditions in your tank are deteriorating.

Dissolved Organics.

Chemical based test kit.

Gives an indication of the degree of pollution resulting from phenols and other organic compounds

Light output.

Monitoring light output tells you when your lamps need replacing. My recommendation would be to record your light output at a fixed distance from the lamp (in the case of metal halide lamps after they’ve been run for around 100 hours) periodically re-check, then when output has reduced by 30% you’ll know it’s time to replace the lamps. When you do replace an aging lamp, always raise the new lamp to a point where you’re getting the same output as the old lamp to avoid photo shock to your corals, and then gradually lower the fixture over a week to ten days until you reach the original position.
As regards the amount of light used, this depends on the corals being kept and on their original depth on the reef.
The most suitable way of measuring light in a reef is to employ a PAR or Quantum meter, this instrument measures photosynthetically available radiation and can be viewed as quantifying the number of actual photons hitting a coral. Forget about Lux or Lumens, these units are biased towards human perception of brightness and are weighted towards certain sections of the spectrum and don’t give an accurate evaluation of light available to drive photosynthesis.

Turbidity.

Turbidity or discoloration of the water can be closely linked to the above notes about photo shock in corals. If your water is discoloured and you respond by adding carbon to clear it you can end up with your corals suffering from photo shock.
This can be evaluated in a number of ways, from the high tech – PAR meter or other photoelectrical sensor, to the low tech – a strip of white plastic part immersed in the water and then visually comparing the difference in colour above and below the water line.

Bacteria.

The measurement of bacteria in the home aquarium is something of a new concept. By using bacteria dip tests in marine aquariums we may be able to learn more about how our reefs are performing by seeing what levels of bacteria are present. Bacteria can have a significant affect on the total BOD and, while many species are benign, others may become pathogenic under certain circumstances. I’ve not yet applied this testing to the reef aquarium but I’m currently looking a bacteria levels in live food cultures and seahorse tanks to see if there is any correlation between the number of Vibrio species present and the incidence of bacterial disease.

Not just the aquarium.

It’s not just the aquarium water you need to test. It makes good sense to look at the water you use for either making up your salt mix for water changes or for evaporation replacement. Testing here serves the purpose of evaluating the efficiency of your Reverse Osmosis (RO) unit or the purity of RO water bought from a shop. Does the membrane need replacing? Are you introducing Nitrate or Phosphate into your aquarium along with your water?
It’s also worth looking at how your salt mix is performing. Is it at the correct salinity? Is there sufficient calcium in the mix? Is it providing a correctly balanced ratio of calcium and carbonates?

Incidentally, regarding RO water, aquarists often query whether RO water is acid – it’s not, it’s neutral, with a pH of 7.0 at 25˚c. The confusion arises from the fact that the pH probes used in the aquarium hobby are incapable of giving an accurate reading when used to measure very pure water.

Afterword.

Whatever method you’re using for testing, try not to get hung up about hitting particular values. All reefs are different and will all display slightly different water chemistry owing to their unique assemblage of animals. Further more take into account the resolution of your testing method; any reading you get will be plus or minus the resolution of the test used.
If your not testing water at the accepted natural seawater level of 35 ppt or at 25˚C your readings will be inaccurate for some of these tests as concentrations will vary with salinity.

Tim Hayes
Midland Reefs
©2006 – 20011

Suggested Reef Aquarium Parameters.

These are intended as a guide for new reefkeepers. Don’t be too pedantic about trying to keep exactly to any particular figure, except where that figure is a zero. Understand that aquarium test kits aren’t spot on accurate but have a resolution of plus or minus X mg/l or ppm, so again don’t worry over much about exact figures, use the results to reassure yourself that you’re within the quoted parameters. Some parameters have more than one measurement listed to take into account differences in how test kits represent the results. There are other parameters of interest in the reef aquarium but the ones listed below are those of greatest importance.

	Range	Target
Specific Gravity	1.022 – 1.028	1.025
Temperature	75º – 82º F	78º F
	24º – 28º C	26º C
pH *	8.1 – 8.5	8.4 daily average
Calcium *	350 – 450 ppm	450 ppm
Alkalinity *	7 – 10 dKH	8 – 10 dKH
	2.5 – 3.5 meq/L	3+ meq/L
Ammonia	0
Nitrite	0
Nitrate – Nitrogen	< 5 ppm
Nitrate ION	0 – 20 ppm
Phosphate	0
Dissolved Oxygen	c. 7 ppm
Redox 325 – 400 mV	c. 350 mV
Magnesium	c. 3 x Ca. level

Notes:

• Salinity. 35 ppt or 1.025 SG @ 25˚C (salinity represented by specific gravity will vary according to temperature). Variation from full strength seawater will give you inaccurate readings on some parameters as ionic strength will be effected.

• pH, Alkalinity, and Calcium, these 3 parameters are interdependent on each other. The relationship between Alkalinity and Calcium should be a balanced ratio supported by appropriate supplementation – these 2 parameters are in a seesaw like balance, as one goes up the other will go down. I intend to add a calculator to the site to make it easier to understand the correct balanced levels for these 2 parameters.

*pH. 8.2–8.5

*Alkalinity (Carbonate hardness). 2.5–3.5 meq/l (7-10 dKH)

*Calcium. 380-450 mg/l

• Magnesium. 1200-1300 ppm. Natural seawater at 35 ppt is around 1285 ppm

• Phosphate. Less than 0.45 ppm (as orthophosphate) Less than 0.15 ppm (as phosphate – phosphorous)

Tim Hayes
Midland Reefs
©2009

In response to a number of queries about low pH in the reef aquarium I’ve prepared this beginner’s or basic article.

First off, do you actually have a problem?

pH fluctuates over the course of twenty four hours in response to biological activity such as respiration and photosynthesis. Generally pH is lowest first thing in the morning before the lights go on, it rises over the course of the day, peaking at lights out in the evening. For this reason, always test at the same time of day so meaningful comparisons can be made.

What should the pH of your reef aquarium be?

A stable pH of between 8.2 and 8.3 is ideal.

What causes low pH?

There are two main causes of low pH in the reef aquarium:

• The breakdown of waste organic material leads to acidification.

• Insufficient water movement can be a cause of low pH readings. If there’s not enough disturbance at the surface of the aquarium CO2 levels can build up in the water, depressing its pH. By increasing surface water movement, the excess CO2 will be gassed off, returning the pH to normal.

Other causes of low pH:

• Additionally, surface bio-films, or cover glasses that fit too tightly with out allowing for ventilation, can be the cause of low pH readings, again because the CO2 present in the water as a result of biological processes isn’t being allowed to escape.

• And watch out for the Christmas/birthday party effect. It’s quite possible for a large gathering of people, in a poorly ventilated room, to contribute to a lowering of pH in your aquarium by putting unusually high levels of CO2 into the room’s atmosphere.

How can you tell if there’s sufficient water movement to facilitate gas exchange?

You can easily test whether low pH is caused by excess CO2. Measure the pH level of your aquarium, making a note of the reading, then immediately take a sample of the water, half a litre to a litre should do. Remove the sample to another room and aerate it for twelve to twenty four hours, then measure the pH of the test sample. If the pH has risen, this shows that excess CO2 has been gassed off in the intervening time, indicating the cause of your tank’s pH problem is an accumulation of CO2.

Does your reef aquarium feature cover glasses or is the top of it enclosed?

The initial problem of utilising a covered design with a reef tank takes us back to the matter of gas exchange. Even if your aquarium has adequate water movement to facilitate gas exchange, the use of a cover is most likely going to lead to a depressed pH. In a reef aquarium pH is critical and should be in the range of 8.2 to 8.5; with a closed tank any carbon dioxide (CO2) gassed off by water movement is going to be held close to the surface by the hood and can be reabsorbed by the water, lowering the pH.  Yes, you can employ fans to ventilate the cabinet but they’re not always sufficient for the job and have the disadvantage that they’re working in a hostile environment, saltwater and humidity, which will lead to a short operational life and hence they’ll need periodic replacement.

Tim Hayes

Midland Reefs

©2009