Seawater Changing

It can be a reef aquarium or fish only aquarium, large or small, but whatever it is there is a need for high water quality. When an aquarium system has been running for a time, the water quality can start to fall.

Good husbandry practices can slow down the drop in the quality of the seawater. Efficient bio-filtration, protein skimmers, perhaps activated carbon, calcium reactors, reverse osmosis top-ups etc all assist. Nevertheless routine water changes are a great aid.

Many of us aquarists are not particularly scientific or technical, but nevertheless it seems obvious that the seawater that filled the aquarium is not going to remain in the same state. The life forms in the aquarium see to that. Their life functions change the seawater state – an example is the pressure on pH. Acidic pressures caused by life forms try to reduce pH, and it is only the buffering capacity of the seawater that resists this. If this buffering capacity, or alkalinity, fails then the pH will be in trouble. So for a start, particularly in a reef system, alkalinity needs to be monitored. This of course isn’t the only change that occurs.

The general guideline for the amount of seawater to change is 10% weekly. This should start as soon as the system is active. By changing routinely the seawater is freshened, and trace elements partially replaced. The possible slow build up of nitrate (and other unwanted items) is reduced.

The 10% guideline is a good starter point, particularly for beginner and inexperienced aquarists, who simply need to know ‘what to do’. Once experience is gained and the trends of the aquarium are understood, then, with care, the replacement amount can be reduced. In some cases it may need to be increased, often because of nitrate worries, which in turn is often because of overfeeding. Overfeeding is a pitfall beginners could fall into. It doesn’t take long to realise the error though. If the amount of seawater changed is being decreased, the amount mixed and placed in the aquarium can be the same but at wider intervals, for example every two weeks instead of weekly. Or the weekly change could be reduced of course.

If the routine change is being altered it is important to monitor the seawater parameters. This can be relaxed up to a point when the checks on quality show that all is well and consistently so.

It doesn’t happen often because dry salt mixes are expensive, but aquarists have been known to do large or very large changes in the belief that it ‘must be doing good because it is fresh’. This has been known with nano systems where a large water change (relative to the capacity of the system) is easily done.

A new seawater mix is heated to the temperature of the aquarium seawater and also mixed with an airstone or a powerhead for around 24 hours before it is used. This is to ensure that the salt has mixed completely, and it is fully oxygenated.

There is more to it than that though. The new seawater is still ‘raw‘. The seawater needs to age and this occurs when it is in contact with all the various influences that make up the captive environment – fish, corals, bacteria, tiny reef life, algae etc. This only occurs within the display system, not in the mixing bucket.

So large water changes done routinely are not good. The change gallonage should be tailored to the needs of the system, and the need is discovered by careful testing and a watchful eye.

In my opinion, all systems should have seawater routinely changed. I believe I’m correct in my belief that the majority of aquarists agree.

There are occasions when a larger water change could be beneficial. For example, a fish only system may have been dosed with copper to fight a disease. At the end of the treatment, activated carbon could be used to clear the seawater. Following this the carbon is disposed of and a larger than normal seawater change completed. This change should not be over large, say 20%. If necessary, the change could be done in two goes spaced a few days apart if the aquarium system is a big one.

Nitrate is a problem in quite a few systems, and aquarists advise doing large water changes to try to reduce the level. It is right to try and do something about excessive nitrate but large water changes are not the best way. They may be a temporary solution.

Nitrate only appears if there is something to generate it. Again, feeding is a regular culprit, and it may be that the aquarist is causing, or partially causing, the problem. There are other potential causes. The need is to discover the reason and rectify it, not reduce the problem by large water changes.

Water changes (of normal proportions) take longer to achieve the dilution result than might be thought. The link below is interesting for anyone who wants this explained. The author uses a nitrate problem as an example, along with others.

http://www.reefs.org/library/article/t_brightbill_wc.html

So routine seawater changes are necessary because they are beneficial. It was, I think, the aquarist and researcher Dr Ron Shimek who found that seawater in a captive system was quite unlike real seawater. Our seawater remains ‘natural’ enough as fish and corals thrive in it, and it is clearly necessary to do all that is possible to keep it that way.

---

Clownfish Anemones

The term ‘clownfish anemone’ is an incorrect description, but it describes them well enough. These are the anemones that clownfish use as a home. Probably nearly everyone, aquarist or not, has seen the amazing sight of an unharmed clownfish within the stinging tentacles.

Some of these anemones are in fact called the Carpet Anemone (Stichodactyla gigantea), the Pink Anemone (Heteractis malu), the Bulb Anemone (Entacmaea quadricolor), and Ritteri Anemone (Heteractis magnifica). There are others.

The anemone is more likely to settle well into an aged aquarium. In other words, a system that has been running for quite a few months as this normally means that it is stable. The bio-filtration has settled down and the rock structures have a population of some algae and tiny life. I know of one retailer who will not sell one of these anemones to an aquarist unless his/her system is at least 9 months old.

There are other points to note. The first is the often repeated one – water quality must be high. It should also be noted that lighting needs to be correct as the anemones contain symbiotic algae (zooxanthellae). In a reef aquarium this is normally not a problem as the corals have the same requirement, but in a fish only system (provided the water quality is high enough) the lighting might need alteration.

When purchasing an anemone be sure that there aren’t any signs of damage, particularly on the foot. Sometimes there is damage in that area as getting the anemone off its rock is very difficult. It is much better if there is a rock attached. It is a good idea that when the anemone has been chosen at the retailers, research the natural colour. If the anemone is not this colour, but pale white (unless its meant to be white) or translucent, don’t buy it.

Also these anemones can grow large. I had one which completely outgrew my aquarium and I had to sadly let it go complete with clownfish (I couldn’t bear to separate them). Research will indicate the chosen anemone’s potential size.

Make sure pump intakes and overflows are guarded. If the anemone does wander as it might (see below) it could get sucked into a pump or overflow and be badly damaged.

Placement in the aquarium is very important. If the anemone is not happy with its position it is likely to wander until it is. Much to the irritation of the aquarist it may decide the perfect spot is on the front viewing glass, or somewhere else that is inappropriate.

The anemone should be placed fairly high on the reef, even on the top. The foot should go in a hole or crevice, as the anemone should be happy with that from a defensive point of view – they can contract into it, at least to an extent for protection. If there is a rock attached already to the anemone, don’t try to take it off. The anemone’s grip is very strong and damage to the foot is likely. Just make a hole for the rock to go into, leaving a suitable crevice or such above as described. If there isn’t a rock attached, the anemone should be placed into a crevice etc and given time to attach. To facilitate this circulation pumps may need to be turned off for a few hours (not the bio-filters if these are pump driven). The anemone should attach quite quickly – much more rapidly than a coral.

So the anemone is in place and has adequate lighting. There is one more requirement, and that is water movement. The surface of the anemone should be disturbed by random water movement (that is, not continuously one-directional). The flow need not be powerful, but moderately so. This can be judged by the tentacles when the anemone is expanded, they should wave about like flowers in a moderate breeze.

It seems anemones are fussy. Perhaps they are, but once settled they will give little trouble if water and lighting quality are maintained.

Feeding couldn’t be more simple. It is reported that the anemones can survive but not grow and multiply from the products of the zooxanthellae only, they need additional food. They are well equipped for this, as they have stings in the tentacles (nematocysts) which are fired into the prey when stimulated and poison is delivered. The food can be a small part of a frozen fish etc, the normal aquarium food used for feeding other livestock. The food should be cut fairly small, defrosted (not in a microwave, use seawater or R/O water) and placed in the tentacles. The anemone will move it to the mouth. If there is a resident clownfish it may well steal the food, even though it is too big for the fish to eat. In this case, place the food as close as possible to the mouth of the anemone and ensure the tentacles take hold. Recalling my clownfish, it would even do its best to pull the food out from the anemone’s mouth. It was always interested in the anemone’s food, even though it had been purposely fed beforehand. Don’t overfeed the anemone, once or twice a week should suffice.

Clownfish will not always take up residence in an anemone, much to the aquarist’s disappointment. Some aquarists declare that this is because they are tank bred, and do not recognise the anemone. I don’t dispute this, but what of the young in the wild, they have no formal education that ’this is an anemone’ but find one nevertheless. In addition, tank bred clownfish are known to adopt an anemone, it has been reported often. Perhaps it is instinct.

I would suggest that failure to adopt an anemone could be because it may be the wrong type of anemone. It is known that different clownfish favour different anemones. In view of this I have added a link at the end of the text so that a check can be made.

Bear in mind when considering an anemone that they are equipped to catch prey. The fish in the aquarium are prey for the most part as far as the anemone is concerned. This could occur when a fish swims close to the anemone and gets ‘blown’ in by the water currents. I recall having my heart in my mouth a good few times at how close some fish ventured, but fortunately a mishap never occurred.

An anemone, particularly if it has an attendant clownfish or two, is a really interesting addition to the aquarium. They need good husbandry and they could get large!

http://www.fishlore.com/clownfishanemonechart.htm

---

Thank You To Our Sponsor

Marine Depot is currently a sponsor of Aquarists Online and both John and I thank them for doing so.

We can both highly recommend that you check out their websites. They have a huge amount of equipment, accessories etc available and they also have some unbelievable offers.

http://www.marinedepot.com
http://www.marinedepotlive.com

You should also have a look at their blog. It is a great read.

http://blog.marinedepot.com

So thank you Marine Depot without yourself this site probably would not be possible.

---

If you are interested in sponsoring Aquarists Online then click here for further information

---

A Bare Bottom Aquarium

Fish only aquariums and reef aquariums are able to maintain high quality seawater nowadays, and this is made easier with the range of efficient equipment available. All things being equal the livestock thrive because of it, and, in a reef, also because of the high quality lighting. Marine aquariums can be really beautiful.

This beauty is of course assisted by the aquascaping. Whatever the kind of system, often live rock is used, or some other decorative kind of rock. Showing off this rock and enhancing the overall scene is the decorative sand.

Some aquarists have a deep sand bed (DSB) in the aquarium. Personally, I prefer them to be in a sump for what is in my opinion good reason, but it is a matter of personal choice. Many other aquarists have a decorative bed which, as the name suggests, is for aesthetic purposes only.

It is necessary to have the decorative bed fairly shallow, around 1″. Also, fine sand (as used in a DSB) can cause problems so a coarse sand is normally used. The problem with coarse sand is that debris can lodge between the grains and eventually the sand becomes dirty. That is why the depth of sand is controlled – it makes stirring the sand easier. Stirring the sand brings out detritus and, if it is not caught by any mechanical filter, it will usually lodge somewhere and can then be siphoned out. Some aquarists are adept at stirring and siphoning at one go.

Other aquarists don’t use sand at all, at least not in the display aquarium. This avoids the work of cleaning of course, and any dirt accumulation can easily be siphoned out.

When I designed and set up my reef, I used coarse sand for decorative purposes. My reef is raised on ‘egg crate,’ and I put plastic barriers on the edges in line with the crate to prevent the ingress of sand under the reef. This worked for a while but was a mistake.

In the process of cleaning the sand, it was impossible not to get sand over the barriers. My reef structure is quite steep and comes within 2 or 3″ of the aquarium glass at the bottom, so there isn’t that much room for manoeuvre.

Realising what was happening, I siphoned out the sand, or as much as possible. It was cleaned and put into a bag for storage.

The tank looked a little strange with the glass showing at the bottom. This didn’t last very long though, as various forms of marine growth, including encrusting algae, soon took hold. It must have been about 6 weeks after the sand was removed that the glass bottom disappeared.

I have a blue damsel in the aquarium, and the fish is very helpful. The sand on one side that got past the barrier has been removed, the fish dumped it back on the outside of the barrier, so I could siphon it out. I assume this is some natural instinct to keep its ‘home’ clear of debris? Whatever the reason, it is a most useful trait. All I have to do now is get the fish to remove the bit of sand at the other end!

It cannot be denied that a decorative sand bed is an enhancement to the aquarium. However, if the bed becomes dirty, it doesn’t take long for those good looks to reduce or disappear. Unwanted algae could also appear on the surface of the sand. It is important to keep it clean, and the best way of doing this is to include cleaning as part of routine maintenance.

If the sand bed is going to present any difficulties because of access for any reason, then consideration can be given to running ‘bare bottom.’ Consideration can be given to running bare bottom anyway as once some time has passed, and particularly in a reef system where calcium and alkalinity are monitored, it won’t be long before the ‘bare’ part is gone. The result is very decorative as well.

---

Two Corals To Avoid

When an aquarium is ready for coral stocking, or is up and running and additional coral stocking is being contemplated, a trip is usually taken to the local retailer to decide on what to purchase. On arrival, more often than not there is a large range of corals on display of both the hard and soft varieties, though the latter may be in higher numbers.

The choice can be bewildering. What to choose? It is said over and over again that research into potential stock before purchase is very important. Inappropriate corals are still purchased though. Many, maybe most aquarists do it. I did.

The corals look so splendid, but there are some that stand out. There are others that really stand out, and it is with these that the aquarist is overcome. So they are bought.

The first is a soft coral. Soft corals are supposed to be ‘easier,’ and so they are generally. There are always exceptions, and this is one of them.

The coral is commonly known under several names- carnation coral, tree coral, strawberry coral and cauliflower coral being some. The proper name is Dendronephthya. There are perhaps 250 different  types under this banner. They are really colourful, coming in purple, red, yellow, white, green, pink and orange. Without doubt they are beautiful – attractive is to do them an injustice. I feel quite certain that they will sell quite easily simply because of their visual appeal.

So what is the problem? Most corals help the aquarist by having symbiotic algae (zooxanthellae), which, with adequate light, greatly assists in the maintenance of the coral by providing food and ridding the corals of waste. Dendronephthya do not have this algae. They obtain food by capturing it. To survive a high level of phytoplankton and possibly zooplankton are required. This means, in a closed system, a great danger of pollution. Also the corals require fairly strong currents to bring the food to them which may not suite some other corals. On introduction to the aquarium, some do not even re-expand. Even if they do they are likely to perish quite quickly. As said, if sufficient food is provided it is likely that the tank will be polluted and then more than this coral will be negatively affected. The only good thing about the coral (apart from its beauty) is that in nature they are found in areas of very low light and also, but less, in areas of sunlight. Therefore it may be that they can tolerate many positions in the aquarium. However, be that true or not, they are not going to survive anyway.

The second coral that requires a mention is for the same reasons – difficulty of maintenance. This coral is possibly even more attractive than the one already mentioned. This is the one that I purchased (once) years ago.

In this case the coral is commonly known as the flowerpot coral or daisy coral. The proper name is Goniopora, and they are hard corals. They can be brown, green, cream, pink or yellow. Their beauty comes not only from the colour but also from the long stems of the polyps, hence the common names. These do look like flowers in a vase, and they sway in the currents in a really attractive way. They can easily be the centrepiece of any aquarium.

They are often sold as a round ball like rock, with the coral covering most of the upper and uncovered surface of the rock. The ’skin’ of the coral seems to be stretched tight over the surface of the rock and this is the first danger. The aquarist can unwittingly damage the coral when putting it into the aquarium if the support rocks are sharp, or there is insufficient support and the coral falls. Great care needs to be taken when handling these corals and their placement pre-checked.

They prefer low to moderate currents because of the long polyp stems, and also bright light. So in an aquarium lit by fluorescent tubes the coral needs to be placed high on the reef.

The second problem is with feeding. It is reported that Goniopora cannot survive on their zooxanthellae, therefore supplementary feeding with phytoplankton is said to be required. So the same problem can occur as with the first coral if due care isn’t exercised – pollution.

Even if all apparent requirements are being met it is likely that the coral will fail. It may last a month or longer, but the high probability is it will die. This happens slowly, the first indication being that the polyps, or some of them, are not expanding as much as they used to. Eventually, the polyps hardly expand at all, and more and more fail to open.

Some aquarists keep Goniopora for a ’long’ period (’long’ in terms of the expected captive lifespan of this coral) which could be 6 months to a year. In my case it was about 8 months. My coral didn’t die because of failure of the polyps, though they were quite short and, if I recall correctly, some didn’t expand at all and some polyps didn’t open, it died after a fall from the rockwork. There wasn’t any obvious damage, but the coral  became covered in a jelly-like substance and that was it.

Very advanced aquarists who may wish to experiment with the captive care of the two mentioned corals could be of great benefit to all of us. Experiments with feeding, water currents and light could be undertaken.

For the rest of us, the corals should not be purchased, and the magnet of their undeniable beauty resisted. As far as I am aware they are not threatened in the wild, but surely it is wrong to sell or buy corals that are very nearly 100% certain to die. Better to leave them to survive with nature until the secrets of keeping them in good health in captivity are known.

---

Should You Run Your Protein Skimmer Full Time Or Part Time?

The protein skimmer assists in the removal of dissolved organic compounds (DOC’s) from the water column. The protein skimmers manufactured nowadays are normally exceptionally efficient – as long as they are kept clean!

So what do I mean by running your protein skimmer full time or part time?

Well basically a protein skimmer which is run full time is turned on 24 hours a day 7 days a week whereas a part time skimmer is on for less hours in the day – 12 for example.

So why would anyone consider this?

You have to look carefully at what you are keeping in your saltwater aquarium. If you are keeping fish only then I would recommend without hesitation that the protein skimmer be run fill time. Fish produce a lot of waste and we have to feed them so the protein skimmer assists in the removal of these items as well as others from the water.

If you keep a coral only or a mixed reef tank then perhaps it could be different. I say the word perhaps as you need to look very closely at what you keep in your aquarium. The reason for this is that we are interested in the load on the aquarium i.e. how much waste is being produced which the protein skimmer can then process. In a coral only aquarium then very little bioload should exist as corals put very little strain on the system. This does not mean that you do not need a protein skimmer as I personally would never have a saltwater aquarium without a protein skimmer installed.

In a mixed reef aquarium then you obviously have corals and fish, therefore like the fish only aquarium the fish are being fed, due to the feeding waste is produced which could easily impact water quality. Yet, how many fish are in the aquarium? How large are the fish?

What you can do is review your protein skimmer over a couple of weeks. Ensure that you have optimum water quality and then check your collection cup at the end of the period and see how much waste has been produced. If the cup is over half full then realistically you probably need to keep the protein skimmer running full time to ensure that everything is removed. If the cup is less than half full then faesibly you could potentially use a part time skimmer.

Of course this is not set in stone as each aquarium system is different. The decision ultimately comes down to you based upon your particular setup.

So why do it?

There is a lot of debate as to how much good is removed by a protein skimmer as well as bad. As protein skimmers have evolved over the years they have become more and more efficient. Due to this efficiency they can remove a huge amount from the water. This is great in one way as it assists us in both creating and maintaining the water quality which our aquarium inhabitants require however what else is removed?

Personally I have absolutely no idea. I am not a scientist and do not have the tools, skills or knowledge to be able to analyse the output from a protein skimmer and see what it contained. All I know is that it is brown and exceptionally stinky!

It is believed that some of the items potentially removed by the protein skimmer is used by corals as food. Corals receive the majority of their energy from the lighting which is provided to them, however they do receive a good amount from food captured in the water. This could be the likes of phytoplankton, zooplankton etc. Have you ever watched a documentary on the television about natural coral reefs? Have you seen how many particles are floating about in the water? Loads aren’t there – in the aquarium we do not have this amount as we have to use man-made devices in order to keep the water clean.

So potentially if you run the skimmer part time some of this life will not be removed and can be used by the corals as food.

There have been reports that when this is performed it has been noticed that the corals appear to have better colour and better polyp extension.

Another method is by actually feeding the corals yourself. You can purchase various ready made containers full of coral food which you feed to the aquarium. There are also various methods you can follow to make your own coral food. I will cover coral feeding in a future article.

Would I do it? – maybe but only if I was absolutely positive that it was not detrimental to water quality and I would be testing the water all the time.

Would I recommend the beginner do it? – Probably not – not just because they are new to the hobby but the aquarium is also new and needs to age a bit. Perhaps if only corals were being kept but even then I think that it should be run full time until the aquarists gains experience.

---

Zooxanthellae

The first thing that needs to be done after writing the above is to ensure the spelling is correct. It is a strange word to us ordinary mortals, but came into being with marine biologists.

In the marine world one of the most fascinating double acts to watch is that of a clownfish and an anemone. The clown swims to the anemone and gains protection from the stinging tentacles, and, though there is argument, the anemone may gain by the clown chasing off unwanted threats to the anemone or dropping bits of food on it. To my knowledge anyway the anemone’s advantage is not fully clear.

The above example illustrates how two different life forms can be of use to one another. There is another that is much more common in marine aquariums. This one is the relationship between corals and zooxanthellae. Zooaxanthellae are in fact single celled algae that live within the tissue of a coral, often called symbiotic algae. Why should this be?

It is thought that the coral uses the oxygen and carbohydrates manufactured by the zooxanthellae. In turn, the zooxanthellae utilise coral waste products and assist in obtaining trace elements from the seawater. It is theorised that up to 90% of the corals required food may be supplied by the zooxanthellae.

For the algae light is very important, as it is required for the photosynthesis process. This is why reef aquariums are brightly lit, some with T5 fluorescent tubes and others with metal halide bulbs. Power output and spectrum need to be correct (power output for the depth of the aquarium). It is thought that the ‘actinic’ fluorescent tube is very beneficial to the zooxanthellae.

A clue as to whether a coral has zooxanthellae or not is in the colour. Generally, it is likely that corals coloured yellow, purple, red, and orange do not have the algae, and corals coloured blue, beige, brown and green do.

Both soft and hard corals may have zooxanthellae. In addition, there are others, such as the aforementioned anemones and clams such as Tridacna.

Problems can arise with this strange relationship but this is not the text to discuss that. Provided the aquarist provides adequate lighting and water quality, then all should be well.

(Reference: Marine Invertebrates. Martin Haywood and Sue Wells)

---

« Previous Page — Next Page »