Enough Light? Must Be

August 29, 2009

Aquarium Lighting

Watching a marine aquarium is a great pleasure and probably one of the major reasons why so many keep them. With a reef system sometimes a new arrival is seen to appear, or a species of coral that is already present appears somewhere else.

On a few occasions I’ve noticed arrivals that must have come in with coral rock, such as a very dark and tiny crab that was very timid and only appeared at ‘dusk’. Its presence was shown by an exploratory claw appearing out of a crevice. The crab hasn’t been seen for a long time and no doubt has gone.

Corals too can appear when new live or coral rock is introduced. In this case the coral type is already present in the aquarium with a fairly large colony, and the new appearance is in a completely separate part of the aquarium.

As far as I can tell, the main colony is a Rhodactis species (the purchase was made years ago and the dealer didn’t have a clue). Rhodactis are also commonly known as hairy mushrooms and mushroom anemones. I think it could possibly be Rhodactis indosinensis – but is this correct as most grow larger than my specimens? Maybe they are Discosoma species. The colony is receiving plenty of light as it is half way up the reef (about half way up the aquarium depth). The new one, however, is not; it is right down at the bottom. The aquarium is 24″ deep (21.5″ from lights to coral). Further, this new growth is at the end of the aquarium and is partly shadowed by another coral.

Is my lighting system powerful? No is the answer, it’s a fluorescent array of five tubes, three marine whites and two marine blues (actinic). They’re not even T5’s, they’re T8’s. The reef is furnished with soft corals and they are perfectly happy but I had to wonder at the growth of this new one. The blues will penetrate well but even so….

The original colony is in an ideal spot apart from seawater flow which is a bit too vigorous, they prefer weak flow. However, I’ve left things as they are as the mushrooms are clearly healthy and open well, though not to as large an extent as with lower seawater flow.

The new one is the reverse; it’s in an area of slow flow. However, as said, I wondered about the light. It has been slowly growing for about 8 months now and has reached a size of 3″ across, which, because of the slow seawater flow, is full expansion. However, though I believed the slow growth must be because of light, or at least the lack of it, it seems this could be wrong. Looking at one of the references available to me * it seems that though light is no doubt an influencing factor it isn’t that important, as strong lighting is not required by Rhodactis species though they will tolerate it. Discosoma species prefer in many cases reduced light.

How did the new growth appear? It is possible it’s by natural detachment, but in this case is more likely to be my error. From time to time I have to get out the trusty and sharp scissors and reduce the colony to prevent interference with other species. Part of this is catching the detached parts. These corals are easy to ‘frag’ so if a small part escaped my attention and lodged it is more than likely to grow.

So there we are – what started as a general belief followed up by some simple research has turned my notion upside down. Goes to show how important basic research is. As far as identifying the species, I’d need a marine biologist and I bet there’d be uncertainty even then.

(*Reference: Aquarium Corals. Eric H. Borneman)


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Remember The Lighting

August 16, 2009

Aquarium Lighting

What is the most important part of a marine system? Lighting? Well no, it isn’t, seawater quality is the number one with both fish only and reef aquariums.

High seawater quality means there shouldn’t be any indication of ammonia or nitrite. Nitrate should be as low as possible (the guideline for a reef system is less than 10 ppm (parts per million) and for a fish only less than 30 ppm. Phosphate should preferably be undetectable. pH should be stable in the region 8.1 to 8.4. SG (specific gravity) for a fish only should be stable within the range 1.022 to 1.025, and in a reef system 1.024 to 1.025 (there are variations with SG which more advanced aquarists use for specific purposes). With a reef system there are more seawater parameters that could be monitored but those given are the basic ones.

So what has seawater quality got to do with lighting, this text is about lighting according to the title.

There are occasions when an aquarist is completely at a loss to explain why the corals are not as they were, with reduced growth and less expansion. Tests have been carried out on the seawater and it is top notch. What could be the problem? Perhaps a disease that is hard to spot? In fact it could be the lighting. Great care is taken when setting up a reef system to ensure the lighting is suitable and the corals, hard or soft, will confirm this.

With a fish only aquarium the lighting is not of such great importance. Its function is to permit the fish to see and the aquarist to see the fish. In addition, if the lighting, which is usually fluorescent tubes, is chosen with care the fish colours can be enhanced. Some colours react really well to ‘marine white’ tubes, and likewise to blue (actinic) ones. There isn’t any reason why more than two tubes cannot be used, but at least two should be in use, say one ‘marine white’ and one blue (actinic). Doing this not only assists with fish colouration, it permits the aquarist to create a ‘dawn/dusk’ sequence. Using electric timers, the blue tube comes on first, then half an hour later the white. At the end of the day the white goes off followed by the blue. This avoids washing the aquarium with sudden light and plunging it into instant darkness, both bad practices.

The reef aquarium is a different story. With these systems lighting is a close second to seawater quality. Most of the corals commonly kept have zooxanthellae in their flesh. Zooxanthellae are single celled algae and the coral gets its colour from them. In addition the corals obtain food as ‘rent’ from the algae; authorities have quoted the level of food supply as 80% or more. Algae, as other plants, require light in order to photosynthesize. The light needs to have sufficient power to penetrate the seawater to the depth of the corals and reach the algae. Power is measured in watts (W). If power is insufficient then the algae will get too little, this is why different power requirements are quoted for aquariums with different depths. In addition, the spectrum needs to be suitable. Light is measured in Kelvin, otherwise known as the colour temperature. Though there is more than one colour suitable for photosynthesis with some corals, blue is the one commonly used by aquarists. Blue penetrates deeply into the seas and oceans. Generally all light types use the Kelvin scale. If metal halide lighting is in use, the bulb(s) commonly used are 10000K and 14000K. The higher the number, the more cold or blue the light appears. Many aquarists use blue (actinic) fluorescent tubes alongside their metal halides. Many commercially produced metal halide arrays incorporate these tubes.

With reef lighting it is also advantageous to have a ‘dawn/dusk’ sequence. Whether the main white lights are fluorescent or metal halide, having blue tubes allows the sequence to be arranged.

So corals, or rather the zooxanthellae in their flesh, need lights that have a suitable colour and in addition the lights need to have enough power to penetrate the seawater.

Provided the aquarist has chosen the correct lighting system in the first place and other requirements are as they should be, the reef display should be lovely. This continues for longer than a year or more when eventually the aquarist notes that the corals aren’t as they were, as said earlier. There appears to be a slow reduction in extension. Perhaps there is a slight and maybe continuing change in colour. Again as said, the aquarist gets out his/her array of test kits but nothing appears wrong, the seawater is still of high quality. How about the lights?

With a fish only system there doesn’t need to be too much concern about the lights. As said they are normally fluorescent tubes and need changing when there is clear discolouration or blackening at the end of the tubes. It is not long after this point has been reached that the tubes are likely to start flickering or fail.

With a reef system the lighting needs more careful monitoring. To the aquarist’s eye there seems to have been no change to the light, as the tubes and/or bulbs switch on normally and they seem just as bright. This is not so however. As time passes the tubes and/or bulbs start to reduce in power which means that, given time, less light will reach the zooxanthellae. In addition, over time the spectrum shifts slowly and the painstakingly chosen lights emit a changed colour, again something the corals will not appreciate.

The best way that a reef aquarist can proceed is to keep a notebook; it only needs to be a small one. In it can go all sorts of memory joggers – including when the lights were first turned on. The manufacturers usually suggest in their documentation how long the lights should maintain their original specifications. There is considerable discussion within the hobby about light reduction/change periods, some suggesting that lights should be changed every three months. I have no facts or scientific reports to argue with, but I feel that period is definitely safe but rather short. Changing the lights no later than one year seems to be a reasonable general guideline. My reef is lit by a fluorescent array, and I change every nine months and have not had any problems.

The aquarist carries out many maintenance activities, a number of which are quite rightly concerned with seawater. There are the test kits that need to come out of the cupboard regularly, the routine seawater changes that partially replace lost trace elements and dilute the sometimes troublesome nitrate. Then there’s cleaning that very useful device the protein skimmer and ensuring that seawater flow is optimal. Plus the rest.

The lights are just there. They may get an occasional wipe with a damp rag but that’s usually all. They’re very dependable and all that is needed is a bulb/tube change after a specific time lapse. This will keep the corals happy if other parameters are good.

Happy corals mean a happy aquarist.


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An Attached Quarantine Tank

July 18, 2009

1160292_82946141Having a quarantine tank is generally accepted as ‘a good thing’. Strangely, the majority of marine aquarists don’t use one, instead throwing caution to the winds or at least relying on good luck. Perhaps they obtain their fish from sources where they are guaranteed to have been successfully quarantined.

Anyway, this isn’t about the merits of quarantine, this is about continuing usefulness.

Quarantine tanks don’t need to be large, just large enough to comfortably hold the largest fish that will occupy them. All the same, it is a little irritating to have an available space doing nothing – the tank sits there empty. The tank can of course be used as a hospital tank should the need arise, but this is hardly ever needed particularly if quarantine has been completed on carefully selected and compatible livestock.

An idea came up recently about a way of using a quarantine tank as part of an overall system so that it wouldn’t sit and ‘do nothing’.

The tank would be selected to ensure it could accommodate anything likely to go in it. It would then be connected into the main system permanently. Err, sorry, what was that again?

Instead of the quarantine tank sitting empty most of the time it would be connected to the main display system as a permanent feature. This gives the advantage that the system would hold more gallons of seawater. It would not be intended to be stocked with anything, just have seawater flowing through it. (Hmm, how long would that last I wonder, aquarists tend to fill empty spaces.)

The tank would be fed seawater that was circulating through the display aquarium and any sump. See the first problem? Of course you can, any problem in the tank would become an available problem throughout the system. Disease for example, the very thing that the quarantine tank is designed to prevent entering the main display.

The idea went on that this problem could be prevented by using a UV (ultraviolet) sterilizer. UV sterilizers (some call them filters) kill or severely damage unwanted organisms as they pass close to the UV light (they do the same to good organisms as well). The seawater exiting the quarantine tank would flow through the sterilizer and therefore anything unwanted would be dealt with. On the face of it this isn’t a bad idea.

The first problem is that the flow rate through the UV unit has to be correct. This is because in order for the UV unit to be effective organisms have to be exposed to the radiation for a long enough period. Therefore the flow rate would probably have to be slowed down.

The second problem is that good as a UV sterilizer is there isn’t a guarantee that all organisms passing though will be killed or sufficiently damaged. Most probably would be or the UV sterilizer wouldn’t exist – but there isn’t as said a surety that all will be properly dealt with. So the system as a whole would be at risk.

The next is not really a problem, more a discipline. The aquarist would need to ensure that the UV bulb, which has a specific life, was renewed well in time or its effectiveness would reduce.

So the basic idea is flawed. However, how about a small modification? How about placing a shut off valve on the outlet from the tank? This would require a complication which is another outlet for the seawater to go through the UV unit. This would be easily achieved by fitting in a correctly rated powerhead to run seawater through the UV unit and back again. Oh, there’d need to be a shut off valve on the inlet to the tank too or it would overflow. Things are getting a bit too complicated. With the shut-off valves at each end of the tank it is now independent of the system.

Many aquarists use a UV unit fulltime or part time or as necessary. Fine, there’s no problem there. Many aquarists don’t use them at all. It’s a choice. But the UV sterilizer is not an answer to the quarantine question.

The only way a permanently attached quarantine tank could work, as far as I can see, is to have stop valves on the seawater input and output. Therefore the tank could not be plumbed directly in line with the display aquarium and sump, it would have to have a direct feed to and from the seawater source which wouldn’t interfere with overall system circulation.

Under normal circumstances (that is, empty without livestock) the quarantine tank would be full of seawater flowing through it, which is an advantage to overall gallonage. If the time came to use it as a dedicated quarantine area, the first action would be to turn off the input and output valves to isolate the tank.

Another problem now arises and that is seawater circulation. Now that the tank is isolated there isn’t any circulation so there would need to be available a low powered powerhead to deal with this. The next problem is that the circulating seawater would cool down, so a small heater would be needed. Then, for the security of the quarantined fish, a suitable clay pot, for example, would be needed as a temporary home.

Light needs to be considered – is there enough light over the quarantine area? Would any need to be added for the comfort of the fish?

Once the quarantine period was over, before the inlet and output valves were opened, all the seawater in the quarantine area would need to be removed. Most could probably be siphoned out. It would be important to dry out the tank entirely particularly if any copper treatment had been used, and probably rinse the area out as well. Not particularly difficult, but another necessity and complication.

All of this leads to the thought that it would be better to stay with the unattached quarantine tank. They are usually small and can be put out of the way somewhere with the powerhead and heater inside.

Having an additional tank attached to the main system isn’t a bad idea, as said it increases gallonage. Also it could house further filtration or even special livestock of interest to the aquarist. There wouldn’t need to be inlet and outlet stop valves either!

There is one thing that must be said and this is that thinking ‘outside the box’ is one of the ways that the hobby progresses, so the aquarist who mused over this idea is to be congratulated – the idea is not practical when examined, but it is an idea.


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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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Is This The Future Of Aquarium Monitoring?

April 9, 2009

For many years now applications have been available which allow you to control various elements of the aquarium whilst you are away from it. The can be simple things such as electrical timers to the more advanced controllers.

There are also some applications which allow you to monitor the aquarium over the internet so that you can check various parameters – again these are normally quite expensive.

Watching the aquarium whilst you are away is very simple as you can just hook up a webcam and broadcast it over the internet.

There is a relatively new one now available and it looks to be very good at first sight.

It is called TankedCAM.

What TankedCAM allows you to do is basically monitor your aquarium whilst you are away from home. This could be when you are at work, travelling, on vacation etc.

TankedCAM gives you the ability to be able to view your aquarium using a live video feed. It also allows you to pan the camera, check water temperature, pH levels, feed the fish and operate various equipment such as lighting, moonlights etc.

Now, this probably does not seem to be that new however there is a twist…

You can watch, monitor and control your aquarium directly from your I-Phone!

They have developed an application designed especially for the I-Phone which allows you to monitor/watch your aquarium and take control of various pieces of equipment. How useful could that be?

It is also available to be used on a PC so if you do not have an I-Phone and are interested in this product then you have not been left out.

As said this product is relatively new and or their website there is a poll running asking what else aquarists would like to monitor so I can only believe that they are hoping to add more functionality to the product in the near future.

I can see so many uses for it.

Below is an excerpt from their webpage:

These technologies are nothing new and can be very expensive to implement separately. TankedCAM is a much more inexpensive way to create an interactive aquarium experience that you can enjoy from anywhere in the world that has an internet connection. TankedCAM is a modular set up that combines these technologies in to one solution and allows you to choose exactly which aspects you would like to monitor in your aquarium.

TankedCAM will be built based on your monitoring needs and shipped to you directly. Set up is as simple as placing the head unit near your aquarium, inserting the water probes (if any) and connecting the network and power cables. In a joint effort with WaveJam Technologies, LLC.  we can also set up and host a special web page that allows you to view your tank from an iPhone or computer web browser.

I do have to point out that this does look good but I have never actually tried it (If the owners read this then perhaps they will ship us a review version – hint hint!) however the images on their website lead me to believe that the equipment looks like it has a high build quality however as said I have not tried it so cannot comment on how robust it is, what it’s expected lifetime is etc.

If you want to have a look yourself then pop over to http://www.tankedcam.com

If you want to have a go with their online demo on your I-Phone then open Safari on your iPhone and type the address m.tankedcam.com into the address bar. If you want to try their PC version then they also have an online demo available on their site.

There is one thing that I am not certain of however, and that it whether the probes will be ok in salt water. Perhaps I will drop them a line and attempt to find out.

Below are some videos which show it in action.


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What Are Moonlights For An Aquarium?

March 26, 2009

For a marine fish only aquarium lighting is simple, the fish need to be able to see and be seen. For a reef system the lighting is more complicated, as not only do the fish need to see and be seen the corals will normally have zooxanthallae within their flesh and this single celled algae needs to flourish so that the coral does too.

There’s a form of lighting that presents not a single headache and that is moonlight.

In the wild as everywhere else there is day and night, plus the transitional periods dawn and dusk. At night there is often moonlight which is missing from most aquariums.

Having moonlight is not essential. Corals are not going to suffer from the lack of it. Having mentioned corals and moonlight, isn’t it fascinating the mass spawning of corals on a reef, all of them triggered more or less at once.

Moonlight is optional. For those well-heeled aquarists with LED (light emitting diode) arrays it is possible that it is built in and ‘on’ times can be programmed. For most of us it is an extra purchase.

When all the lighting is off except for moonlights the effect on the captive reef is lovely. Weak shafts of light descend onto the corals, flickering across them. It can make the night period quite beautiful and draw the aquarist to have a look at a time when usually he/she wouldn’t.

Moonlights are a small array of blue LED lights. Usually they are supplied in a small unit, with perhaps five or less LED’s. There are larger units. Sometimes they are powered by a plug-in transformer style electricity supply. Their demand for electricity is very low, so very little will be added to the electricity bill.

As said, putting moonlights onto an aquarium is optional as there isn’t a technical requirement. Very advanced aquarists could well experiment with them to see if corals could be induced to spawn though this would be difficult and time consuming. Most of us would use them purely for the lovely effect, and expand the period when the aquarium acts like a magnet.


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Are Rotating Powerheads Any Good?

March 9, 2009

There are several important factors that should be present if a marine aquarium is to be a success. In both fish only and reef aquariums seawater movement is one of them.

One reason for the importance of movement is oxygen intake, if it is adequate the seawater will constantly reach air/water interfaces, in particular the display aquarium surface, where gas exchange can take place. Another reason is that it assists corals obtain food and rid themselves of mucus.

There are several ways of providing adequate movement, some advanced and some ‘basic’. It is likely that many (most?) aquarists use ‘basic’ equipment, namely powerheads. These devices are available in more than one type, though they are all basically an electric motor made seawater safe by encapsulating it in resin, the motor drives an impellor, and there is a seawater intake and outlet. The powerheads could be narrow outlet or wide (‘soft’) outlet types. The wide outlet ones are able to move large quantities of seawater but because they push out the seawater on a wide front the impact is soft and not harmful to corals, particularly if there are two in opposition or they are timed. Narrow outlet powerheads pump a much thinner stream of seawater which is very linear and can damage fairly close corals because of the force.

Random and chaotic seawater movement is the aim and this is often obtained by placing powerheads in opposition to each other and also ‘bouncing’ the outlets off the glass. This should result in the desired seawater flow once a bit of trial and error with powerhead positioning has been completed.

With the narrow outlet powerheads there is a further option and this is to use the generated flow of the seawater to drive a mobile directional outlet. This type of outlet can be bought as an ‘add on’ or alternatively a powerhead obtained which has the required outlet fitted. What happens is that the flow of the seawater from the powerhead causes the outlet to swivel from side to side in an arc. The movement of the outlet is not particularly fast and when the end of the arc is reached the direction is reversed. Another method is an outlet that spins, the seawater acting something like jet propulsion driving it round.

This idea has merits. The seawater flow is automatically being re-directed continuously which is good and in itself is going to create varying currents in the aquarium. If there are two powerheads present, for example, and each has a rotation ability then continuously varying seawater flow will be generated at each end of the aquarium. In addition, from time to time the outlets will come into direct opposition to each other and create more random currents.

Of course there have to be disadvantages! First of all, the rotation is driven by the outlet from the powerhead which detracts from the strength of the flow, though this could be compensated for by the powerhead strength itself. The rotation mechanism is submerged in seawater and there is the possibility (probability?) that the rotation will slow down or cease because of calcareous build up. Also, the seawater from the outlet is still linear even though it is rotating, though it would hit a coral that is in the way X number of times per minute rather than continuously. Standard powerheads require their outlet strength checking from time to time and in addition the rotating powerhead needs checking to ensure the rotation mechanism is operating correctly, meaning there is a small addition to routine maintenance checks.

Rotating powerheads are a useful idea and I have nothing against them. However, and this is purely personal, I prefer standard powerheads that have been correctly sized and placed. Better in a suitable aquarium would be wide or ‘soft’ outlet powerheads in opposition, or timed.


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