Why Should Alkalinity Be Higher In The Aquarium?
June 28, 2009
The marine aquarium can be so beautiful if the aquarist does straightforward routine maintenance as required, and doing this maintenance includes attention to the all important seawater quality.
Seawater quality is maintained by routine changes of sufficient quantity, and at the same time tests are completed to ensure that the required standards are met. These tests include specific gravity (SG), pH, nitrate and for a reef could include calcium and similar. Some aquarists continue to test for ammonia and nitrite after the initial maturing process. Alkalinity is a test that is useful to marine systems too.
It would seem fair to think that Mother Nature would know best in these matters and the alkalinity level in the wild is 7 to 9 KH*. So perhaps we should keep out aquarium seawater at the same level.
We could maintain a natural level and hopefully all things being equal there wouldn’t be any problems. However, we are not talking of the vastness of the seas and oceans where seawater quantity is measured in cubic miles; we are talking about aquariums where even a large home system of 500 gallons is, by comparison, very tiny.
Most aquariums are fully stocked whatever system they are. The life in the aquarium puts pressure on the seawater in several ways and one of them is the acid/alkalinity balance. We know this measure as it uses the pH scale, and we want a pH of between 8.0 and 8.4 which is on the alkaline side. The life functions in the aquarium constantly try to reduce this pH towards the acid side, something we do not want.
Prevention of the reduction in pH is achieved by the ‘buffering’ capacity of the seawater, in other words its ability to resist changes caused by acidic substances. The ‘buffer’ is mainly the carbonate/bicarbonate content of the seawater. In certain circumstances the buffer could be seriously weakened or even exhaust and the pH would fall which is detrimental to the livestock.
Dry seawater salt as purchased by most aquarists for seawater make-up has a buffering capacity usually around natural levels. However, many aquarists boost the buffering capacity of their seawater by adding carbonate/bicarbonate powders. These powders are usually mixed in some seawater before being added to the aquarium, being careful not to hit corals etc. The powders are sold commercially and are very easy to use.
In an aquarium it is considered best to maintain alkalinity from 8 to 14 KH.* It is not recommended to raise the level above 14 KH.* The recommended level of 8 to 14 KH does not mean the level can vary within these limits, it should be reasonably stable at the chosen point, ‘reasonably’ meaning that some variation over say a week will not usually be harmful. My system runs at 10 KH and needs boosting to an extent weekly.
If the aquarist measures the alkalinity of a fully stocked system on a weekly basis and keeps a note, then the trend of the aquarium can be seen. The amount of buffer that needs to be added is easily prepared week to week. Testing can be reduced once this requirement has been discovered but should not be abandoned.
If pH is a problem and it is falling despite routine seawater changes and good husbandry in feeding etc, then perhaps the buffer capacity needs attention. Increasing the buffer by 1 KH week to week will not do harm. I have found a good alkalinity level is also beneficial to the growth of welcome encrusting algae which can beautify the aquarium.
By the way, if the desire is to measure alkalinity by mg/l, then multiply KH by 17.9.
(*Reference: Marine Atlas. Helmut Debelius & Hans A. Baensch)
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The Long One
June 7, 2009
Like the majority of aquarists I have a schedule for maintaining my aquarium. With the commitments I have and the time available I’ve found that this schedule saves time - usually.
Saving time doesn’t always occur, sometimes, and it is infrequent, something occurs which takes up a lot more time. Not today though, all went well mainly.
My schedule depends on a number. Number one is clean the glass. Wow, that’s it! Number two is the same as one plus the intake filters on some powerheads, plus a routine seawater change. Number three is the same as one. Number four is a comprehensive clean. Included with all of these numbers is a check for any unwanted organisms such as Aiptasia. So as can be seen maintenance covers a four week cycle.
Maintenance is nearly always done on a Sunday as there is time available, in the morning anyway. It all sounds a bit military maybe, but it works.
The number for today is four, the long one. New seawater ready and waiting, cleaning equipment near the aquarium. The aquarium is surrounded by carpet, so polythene covers are in place. They catch the drips and minor splashes very well.
The very first thing is to clean, with a hard toothbrush, my miniscule algae scrubber. This developed by itself and is obviously doing something as it exists! There must be some level of nutrients in the seawater feeding it. The photo shows it - I did say it is tiny, about 3 inches across and 2 inches deep! The seawater flow is from the hang-on skimmer.
Next the bracing struts and viewing glasses are cleaned with an algae magnet. Only the front and one end viewing glass are done, encrusting algae is permitted to grow on the others.
Exciting stuff this isn’t it! Now the four powerheads which sit in a small compartment are checked. The powerheads driving the under-reef spray bar and anti-phosphate filter have sponge intake filters and these need thorough attention. The anti-phosphate filter is shown in the photo; it is a homemade hang-on type. (Taking the photo was difficult, it is under an open stairway and space is restricted.) The other is an anti-nitrate filter, again homemade but this isn’t in use.
This maintenance is progressing well. The Eheim canister filter is next, the mechanical media has to be checked. This is comprised of fine and medium sponges and it can be surprising how much they catch from what appears to be clean seawater. I have to save numerous very small shrimps as well; these are placed in the display aquarium ensuring the fish don’t get them. There are numbers on the filters - this is from when they were both used for biological purposes so that they could be selected for cleaning, this doesn’t apply now as the biological media has been removed.
Getting there now and it is usually at this point that a cup of coffee appears. Thanks!
Siphoning is next on the agenda but before the main siphon tube is used, I attack any unwanted organisms. Today I located a few Aiptasia and these were dealt with. I’ll have to deal with more as time passes; they are never eliminated, probably because there are so many nooks and crannies in a reef aquarium. As long as they are not left to their own devices for too long they aren’t a problem.
So out come gallons of seawater with the siphon tube, this seawater will be dumped. (I used to use it for brine shrimp production but no longer do so.) At this time any debris spotted on the base of the aquarium is removed. There isn’t much base to be seen but it is checked anyway.
The new seawater is placed on the stairs above the aquarium and my wife kindly makes sure the tube doesn’t come out (not the siphon tube, one that is considerably longer). In goes the seawater.
Not quite done. I manually add certain additives to the seawater, these being calcium, bicarbonate and carbonate powder (for alkalinity) and iodine. Calcium is maintained at around 420ppm and alkalinity at around 4.0meq/L. I don’t measure the iodine level as it is only added once every two weeks at the minimum dose, there has never been a problem.
Nearly time to pack up now, just give the glass bracing struts a clean with a paper towel, likewise the viewing glasses. A check with the hydrometer is required, this is fine at 1024.
Final job - give the fluorescent tubes a wipe. Now it’s all done.
No, not quite. The two fish get some brine shrimp for being so patient!
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A Question About Algae
May 31, 2009
Algae could be the aquarist’s friend and at the same time an enemy, it all depends on what type it is. A question arose recently about algae and my immediate reaction was ‘Oh no, not again, algae!’’ In fact it wasn’t so bad.
The question came from a beginner aquarist who openly admitted that she didn’t have much experience. In fact, she had done precisely four routine seawater changes with her new aquarium. The aquarium, a fish only, was not overstocked, if anything it was understocked. She was a little fed up; the excitement of actually seeing some life in the aquarium after all the patient waiting when the system was being put together was being spoilt by the dreaded algae. I was unable to see the aquarium.
Basically she had done seawater changes and after each one she advised ‘red’ algae had gone bananas. That’s what she said; I don’t think it could have been quite as bad as that!
Many aquarists have problems with various types of algae, particularly when inexperienced and when the aquarium is in its early days. I was surprised that it was red algae causing the trouble. Usually it is green hair algae, or so-called slime algae or smear algae (a thin sheet that slowly covers rocks, sand etc). Slime algae can be ‘reddish’, very dark and appear red nearly black. Another type is diatoms that are usually more golden brown in colour.
Red algae can be calcareous and branching or encrusting, or have flexible ‘leaves’. These algae types are often sort after by aquarists as they are decorative. In the red algae family there are over 4000 types. The algae though had been identified as a problem and not decorative so it cleared these types away. So the algae in question had to be a problem type, but what? Green hair algae was obviously not the answer.
When an aquarium is first started up diatoms often appear. They could cover rocks, sand etc. The diatoms rely on silicates in the seawater - if the silicates go so do the diatoms. If they appear then die back, the silicates are used up. If they then re-appear at a routine seawater change, then more silicates have been introduced. The fresh water source could be suspect. Dry sea salt does not usually cause this type of problem.
Smear or slime algae is a bigger problem. It can be quite difficult to erase but this can be achieved. The presence of smear algae suggests excess nutrients in the seawater, even in a new aquarium. Also smear algae does not like strong currents - it often tends to appear in quiet areas of the aquarium, though just to be helpful it can appear in more turbulent areas.
10% of the net system gallonage is the guideline amount for routine seawater changes, until the actual needs of a particular aquarium are known. The changes being done were of this amount.
Possibilities would have to be narrowed down, so the first suggestion was that seawater tests should be done, that is, nitrate and phosphate. A request was made to test both the seawater in the aquarium and the new seawater made up for a routine change. Ideally, in the aquarium nitrate should be as low as 10ppm (parts per million) or less particularly for a reef aquarium, a fish only could be higher but should still have nitrate minimized. Phosphate should not be detected at all hopefully, but at least the level should not be more than 0.03ppm. If it is higher, say 0.10ppm, it is too high. In newly made up seawater there shouldn’t really be any presence of nitrate or phosphate. Nitrate and phosphate are known problem algae nutrients, thus the need for control.
It turned out that nitrate and phosphate were present and ‘a little too high’, levels were not given. The seawater destined for the routine change was also tested - the same for nitrate. Now then!
So on to the next possibility. This follows the clues given - the algae become more apparent after a routine seawater change and nitrate was present in the new seawater. A check was suggested of the freshwater being used.
The information arrived that the nitrate level in the freshwater was ‘high’. Maybe this was tap water, the most likely, or it could be local spring or well water, I don’t know. Nor was the actual level given. However, ‘high’ in this instance meant ‘too much’ and this seemed to be the problem that needed to be dealt with.
Tap water is not necessarily as pure as might be thought. In agricultural areas there could be excessive nitrate levels. There could also be heavy metals, pesticides, phosphate, chlorine, chloramines and so on. The water is made safe for human consumption; there are regulations as to how much of what is permitted.
The suggestion was made that fresh water should no longer be used from that source, and that a reverse osmosis (RO) unit should be obtained. The RO unit is a membrane that only permits pure water to pass, or nearly so. The purity is usually about 95 to 98%. It is important to have a unit that incorporates a carbon filter at the front end; this protects the membrane as chlorine is removed. Chlorine could damage the membrane. A sediment filter is often incorporated before the membrane as well. RO units come in various ‘gallons per day’ sizes, one needs to be picked that is suitable for the size of the routine seawater change. RO units are very reliable and only require the carbon filter etc changing from time to time in accordance with the manufacturer’s directions. They are not particularly expensive either.
It is worth using high quality fresh water obviously for the welfare of the livestock; also dry sea salt is not cheap. Dry sea salt manufacturers produce salt that is free of nitrate and phosphate - why spoil this with poor fresh water?
Much later on it was learned that an RO unit was in use and though nothing had happened for a while, in time the algae (‘slime’ I assume) started to reduce and the aquarium became clear of it.
This seems a good demonstration that the aquarium will reflect what it receives. Feed in algae nutrients and algae could appear. In this case all turned out well.
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How Gallonage Matters
May 10, 2009
No matter how big or small an aquarium is they all have a gallonage which is often stated in the manufacturer’s documents. Some aquariums are of a standard size and are known as a ‘fifty’ or whatever.
The gallonage quoted in the aquarium name or manufacturer’s documents is with it empty, it has to be this way as of course the manufacturer has no idea of what use the aquarium will be put to and what will be inside it.
As far as the marine hobby is concerned, the quoted gross gallonage can be ignored, it is irrelevant. What is of interest is the net gallonage, the amount of seawater the aquarium can hold once all the decorative whatnots are installed. In the case of both a fish only and reef aquarium, whether live or inert rock is being used doesn’t matter; it is the amount that is installed that does. In the first place, if live rock is being used there must be enough to provide adequate bio-filtration for the full bio load. Secondly, the more there is of either rock type the less the seawater gallonage will be.
If the aquarist decides to use a DSB (deep sand bed) or plenum then this will again reduce the seawater gallonage. A decorative sand bed is not as deep but still accounts for lost seawater space.
So it is important that the aquarist is aware of the net gallonage of the aquarium. Having a sump has advantages and one of these is that the net gallonage is increased.
Calculating the net gallonage could be a hit and miss affair. Probably the most accurate way is for the aquarist to measure the prepared seawater as it goes into the aquarium on the first fill. However, many aquarists mix the initial seawater in the aquarium, but nevertheless a note could be made of the amount that goes in. If any of this first fill is eventually removed because of overfill it needs to be deducted of course. There are helpful gallonage calculators on some marine forums for those who did not measure the ingoing seawater, though accuracy will be lower.
Both the reef and fish only aquarium rely on net gallonage for stocking levels. This is for fish; corals present a much lower bio load. The reef aquarium carries less fish than a fish only system which gives regard to necessary seawater quality. With both systems seawater quality is the number one requirement - how can the aquarist stock correctly if the net gallonage is not known?
When calculating stocking levels for whatever system, the sump seawater should be ignored. The seawater in the sump is not available to the fish and should be viewed as a quality enhancement advantage.
Stocking to the gross gallonage of the display aquarium, or to an overestimated net gallonage could lead to trouble. The aquarium could be and is likely to be overstocked. If there are too many fish there is greater pressure on the seawater quality. In addition it creates more work for the bio-filtration. Further, if there was a temperature increase there could be oxygen problems. The fish obviously require sufficient oxygen, and so does the bio-filter, or rather all the oxygen hungry bacteria in it. If there are problems with the bio-filtration then real trouble could begin.
Also, overstocking can mean overcrowding. Fish will argue and even fight over the right to territory, some more than others. This could lead to fish not eating properly because of stress. On the wild reef fish have plenty of hiding places and in addition if they need to retreat there is plenty of space to do so. Within the strict confines of an aquarium where does a fleeing fish go?
So it is certainly to the advantage of the aquarist and his/her future enjoyment of the hobby to go through a careful initial procedure. This includes research into compatibility with tank mates and aquarium type of course, but should also consider the space that is going to be available. During reef or aquascape construction the aquarist should give full regard to supplying sufficient homes for the number of fish it is intended to keep, many commonly used rocks are helpful with this because they are of very irregular shapes. It will pay off as fish that are settled and secure will be healthy and show the colours that nature intended.
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Algae - Friend Or Foe?
April 28, 2009
Mention the word ‘algae’ to different marine aquarists and the reaction could be mainly one of two, a look of horror perhaps bordering on panic or a smile and a nod. It all depends.
To some aquarists algae is most definitely a foe. These aquarists are, in the main, novices who are gathering experience and have found out the hard way the consequences of over feeding, over stocking, or over lighting. There could even be a combination. One consequence is long hairy green stuff waving in the currents as though it is making fun of the suffering aquarist. Green filamentous algae can spread to such an extent it overgrows the whole aquarium! It seems to be hardy too, as even if the nutrient level is reduced the monstrous stuff seems to survive for quite a while. It takes the nutrients out of the seawater of course which is the only saving grace I can think of. No, there’s one more, which is that it is food for some fish. Nevertheless, it is not required in abundance.
Similarly, slime alga is a problem. This time it is like thin semi-solidified goo on surfaces which is capable of suffocating the life out of anything it covers, again definitely not required. Fortunately it can be siphoned out at routine seawater changes but tends to linger for a while.
So who smiles at algae? It has to be those aquarists who have control of their aquarium conditions. Seawater parameters are as they should be and not permitted to be anything else. Some of these aquarists use algae to combat other algae, which sounds like justice to me! For example, nitrate and phosphate are implicated in the growth of nuisance algae. The same nutrients are necessary to some decorative algae. So, take some decorative algae, such as the Caulerpa macro type, and grow it in reasonable quantity in favourable conditions. If the bad algae is being physically removed and the good algae is taking in nutrients and in favourable conditions, which will lose out? It is likely to be the bad algae. Many use the system and it is definitely helpful.
Have a look at the imported photo with this text. Is that some of the hairy stuff I see?
I’m going off track a little but remaining with algae. Here’s another positive for algae which could develop beyond the intended stated use in a few years. Hope it proves to be of huge benefit!
http://coast2coastam.net/?p=198
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Cool It
April 25, 2009
The most popular lighting for reef aquariums, or to be more specific SPS reef aquariums, continues to be metal halide. This is because metal halides emit a very intense light that has considerable seawater penetration strength as far as aquariums are concerned. Metal halide bulbs are also available in the Kelvin range desired by reef aquarists.
There are two major disadvantages to metal halide lighting systems, the first is cost as they are electricity hungry. The second is heat emission which could be a problem in itself or cause a minor problem to become a major one.
With air temperature warming up for the summer the heat emission from the metal halide bulb(s) doesn’t alter, but the increased air temperature does mean that the aquarium seawater will naturally warm up. This in itself isn’t a bad thing as the heaters will not activate as much saving the aquarist money. Unfortunately, heat output from the lighting can increase the seawater temperature even more, moving it passed the design level. The heaters will of course not activate but these high temperatures are detrimental to the aquarium, for a start it upsets the stability of the system. Increased seawater temperature also reduces the amount of oxygen the seawater can hold, so in say a heavily stocked fish only aquarium there could be trouble. If temperature climbed excessively trouble could occur in any aquarium system. The bacteria housed within the bio-filter that are dealing with the toxins in the seawater are also consuming oxygen which could exacerbate the situation.
So overall it is undesirable for the seawater temperature to climb excessively. There are ways of cooling things down though and with metal halide this is a need that is more likely to be encountered.
Some aquarists counter the effect of the metal halides by cooling down the seawater itself. They do this by employing a chiller (a cooler) which must be specifically designed for marine use because of the very corrosive action of seawater. The chiller needs to be sized correctly or it could be ineffective, a check needs to be made to ensure the device is able to deal with the gallons of seawater involved and also the temperature reduction required - as far as the latter is concerned, if the chiller is matched to the gallonage it should be adequate as there is a temperature adjustment range.
There’s nothing really wrong with using a chiller as described. However, if the sole use of a chiller is because of the heating effect of the lighting it is not really economical. The lighting is consuming electricity which cannot be avoided (except to ensure the bulbs are correctly sized and the lighting on period is not excessive). A chiller is quite an expensive piece of equipment and quite expensive to run. If the seawater heats up anyway quite apart from the lighting fair enough.
If it is mainly the lighting that is causing the seawater temperature problem it is better to tackle the problem at source. Some free hanging metal halide canopies have fans built in which help direct the heat away from the seawater. The biggest problem is likely to be found with those lighting systems that are enclosed within a hood which sits directly on top of the aquarium. These canopies are often an ‘all in one’ build with the canopies matching the aquarium stand.
If the canopy is as described it could have been supplied commercially or been a DIY project. Commercial ones sometimes have fans built in, but not always. Some have air vents at the top and that’s it. These air vents do release heat as warm air rises, but the heat release is too slow and doesn’t deal directly with heat into the seawater. Fans are reasonably easy to install.
There are two ways of installing the fans; the first is to have two fans, one at each end, with an air vent in the middle at the back, and the second is again to have two fans but no air intake at all. In the second version an air vent could be fitted either in the middle or above, it will not do any harm. The idea is to direct a cool air flow across the space between the metal halides and the seawater surface.
Metal halide canopies are of necessity quite large with a good space above the seawater surface, so there should be plenty of room to fit a fan at each end. Some aquarists use computer type fans but the danger with these is that they may not move enough air to deal with the heat. A better option is to use mains electricity powered fans. The ones that are useful are those smaller units that are fitted into bathrooms as extractors; they are usually a small plastic box with vents each side and the fan already mounted inside. Some of these type fans are reversible, that is the fan direction and therefore the air flow can be reversed. If two of these fans are obtained one can be fitted at each end of the lighting canopy. Two holes will obviously need to be cut but if the edges are a little ragged the fan units could fit on the outside to cover them up, the units need to be checked for this option. Some units have a removable outside cover which also fastens the main unit on the inside securely.
In the first option the fans are fitted and there is an air vent in the middle of the canopy back plate. The fans are set so that they both suck in cool air from outside the canopy. This causes an increase of air pressure - not a lot - inside the canopy and the air escapes through the air vent taking heat with it. Care has to be taken that the air doesn’t escape downwards towards the seawater or the cooling effect could be partially or wholly lost.
The second method, with or without an air vent, is probably the best. The fans are fitted at each end of the canopy but this time one fan, it doesn’t matter which end it is at, is set to suck air in. The opposite fan is set to blow air out. This means that there is a powered cooling air flow through the lighting canopy. If there is an air vent some air could escape, but again heat will go with it.
The paragraphs above are concerned mainly with metal halide lighting, but those aquarists who have fluorescent lighting such as T5’s or earlier types could be surprised at how much heat actually builds up in the canopy. A fan cooling system could be an advantage.
There is a major point that needs to be mentioned and this is concerned with safety. Electricity incorrectly used is dangerous. The fans need to be securely fitted and not subject to splashing. Wiring to the fans needs to be completed safely, with the wires going to correctly fused power outlets, and the wiring obviously needs to be properly secured, not trailing. Any doubt and advice from someone competent should be obtained.
Preventing the lighting system from overheating seawater is generally simple and can be done in a way which minimizes the additional electricity demand.
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I Know About Seawater Quality, But…
April 21, 2009
Marine aquarists aim to maintain seawater which is of the highest quality. The reward for doing so is a vibrant aquarium, be it a fish only, corals only or mixed reef, and without the intrusion of nuisance algae.
‘Quality’ means the seawater is stable, the pH in the region 8.0 to 8.4, nitrates in a fish only at 30 ppm (parts per million) or less, in a reef system 10 ppm or less, and phosphate preferably undetectable. If the aquarium contains a captive reef the aquarist will quite likely maintain alkalinity, also calcium if this is relevant to the livestock. However, for the purposes of this discussion quality means stable pH and ‘proper’ nitrate and phosphate levels, that is, they are within the guidelines.
Aquarists complete routine seawater changes which go a long way towards maintaining high quality. Any undesirables in the seawater are diluted and, at the same time, trace elements are replenished or partially so. The seawater could be said to be freshened. The initial guideline amount for routine changes is 10% of the total net gallonage of the system weekly. This therefore includes any sump. There isn’t any requirement to change 10% every week; the aquarist could find it more convenient to change 20% fortnightly. However, a weekly change probably contributes to stability in itself, as the change caused by raw seawater being added is smaller.
pH as said could be anything between 8.0 and 8.4. Whichever the measurement is it should be reasonably stable. It is possible, in some circumstances probable, that there will be a fluctuation in pH between the lights on and off periods. This is normal as it has to do with seawater dissolved gas levels. If there is an excessive reduction, or any reduction which worries the aquarist, one way of combating the change is to employ algae in a sump. The macro algae Caulerpa is commonly used and is lit by fluorescent tubes which have an opposite cycle to the display aquarium lights, which means that when the display aquarium is lit the sump is not and vice versa. Plant growth tubes are often used to assist the Caulerpa, these tubes have a lower Kelvin rating than lights commonly used on a display aquarium. The Caulerpa will also act as a natural filter to combat nitrate and phosphate.
Sometimes pH is not varying excessively, it is just too low. If the reading is consistently too low, and by this it is meant below 8.0, then it is possible that the system does not have efficient enough gas exchange. Gas exchange occurs at air/seawater interfaces, particularly at the aquarium surface. It also occurs on protein skimmer outlets, weirs and the like. It is at these interfaces that the seawater takes in oxygen which is clearly important for livestock. Too low an oxygen level could have serious repercussions for the livestock under certain circumstances, and it could also be the cause of a low pH reading.
Testing the seawater for sufficient oxygen relevant to pH is very easy. Measure the pH of the seawater in the aquarium and make a note of the result. Siphon a gallon or two of seawater into a safe bucket, the one used for new seawater will do. Importantly maintain the temperature so it is the same as the aquarium and also circulate the seawater vigorously for two hours or so. The heater used for new seawater will be fine, also the powerhead or air pump. Note that the seawater needs to be moved vigorously, if it is sluggish it will not do.
After the required time measure the pH of the seawater in the bucket. If it is the same as the aquarium then seawater movement in the aquarium should be adequate. If the pH is higher than that in the aquarium then increasing seawater movement in the aquarium should be beneficial. Sometimes an additional powerhead will do. Place it about half way down in a convenient and hopefully hidden from view spot, and point the outlet at the surface or at an angle across it. Seawater will be moved either in a mound at the surface or a stronger flow will move across the surface. In either case gas exchange should increase affecting the pH. Before an additional powerhead is used it could be worthwhile checking the positions of existing devices.
If the pH is too low and the above test doesn’t make any difference, maybe the alkalinity is also too low. Keeping it brief and basic, seawater is on the alkaline side of the pH scale. Life actions of livestock continually try to push the pH towards the acidic side, particularly in heavily stocked fish only systems. Increasing the alkalinity could maintain pH at a more desirable level and is worth trying. If alkalinity is adjusted it is usual to keep it above natural seawater levels. If it is intended to try this, then there isn’t any mystery or need to explain measurements. Test kits and adjustment powders are commercially produced and easily obtained. The instructions will explain all and there will be a measurement chart included.
The aquarist could be having trouble with nitrate and/or phosphate. If routine seawater changes are properly done and excessive readings persist there are checks that should be initially considered.
First is feeding as this is the major culprit in many seawater quality problems particularly with novices. Nitrate is a product of the nitrogen cycle and is the end product with a canister filter. Even the acclaimed live rock cannot deal with some nitrate readings. Phosphate is mainly introduced to the seawater by feeding. Both nitrate and phosphate have been implicated in problems with nuisance algae, so excessive readings need to be reduced. There is information on feeding techniques in the Articles section on aquaristsonline.com, so further explanation will not be given here. The tendency to overfeed usually has two causes, the first being the pleasure of feeding and the second the concern that the livestock get enough. Both are good reasons, but the act of overfeeding will do harm. As said, the first action is to carefully check the method of feeding and the amount fed.
Nevertheless, some aquarists have trouble anyway, despite being disciplined when feeding and despite doing regular seawater changes. It has already been stated that the initial guideline for routine seawater changes is 10% of the total system net gallonage. Note the word ‘initial’. It may be that the amount changed needs to be increased. It could very well depend on the livestock load. A fully and correctly stocked mixed reef system will usually have a lower bio-load than an equivalent sized fully and correctly stocked fish only system. Fish present a heavier bio-load than corals. So for example in a fish only system there is heavier feeding because of the higher number of fish and of course the fishes life cycles continue. Thus there is more scope to see excessive nitrate and/or phosphate readings. The answer here is probably dilution. In other words an increase in the amount of seawater changed routinely. If the aquarist is changing 10% this could be increased to 15%. Have the readings begun to subside? The readings will gradually subside, as additional pollution continues to be produced - it will not suddenly or quickly disappear. If not, try a further increase to 20%. It is not normally recommended to change more than 25%.
It has to be reiterated that increases in the gallonage of routine seawater changes come after the aquarist is fully satisfied that other avenues to solve the problem are exhausted, such as the mentioned feeding. It is also important to examine carefully the filtration which in the first instance should be adequate. Filtration to combat nitrate and phosphate could be increased. In the case of nitrate more live rock for example, and/or if there is a sump the introduction of a DSB (deep sand bed) and perhaps some Caulerpa algae. In the case of phosphate perhaps an anti-phosphate resin filter could be considered.
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