[kevinpo]

What's all this talk about water flow and corals?

Corals being for the most part stationary need to have their food brought to them and their waste products carried away. On the reef the wave action surging in then draining back out provides this service. Different species of corals populate certain areas of the reef where the flow suites their preferences. The water flow varies greatly depending on location and this along with lighting intensity are two important factors that determine coral species location.

To provide the best environment possible for our corals we must try to duplicate this flow somewhat. At first it may seem fairly easy by using a few powerheads, but this can be more difficult than it seems. Standard powerheads blow constantly in one direction. An improvement on this is the addition of some type of on/off device that turns the powerhead on and off, but some pumps/powerheads will not take the constant starting and stopping and will soon fail. There are also sweeping devices that work well but require a separate pump to drive them and can be hard to mount so they reach the corals. Surge tanks can be noisy, take up space, and produce salt spray. There are also power driven ball valves and other switching devices. There are even microprocessor-controlled pumps that you can vary the amount of flow as well as the duration and even a night cycle.

Although it may sound like a daunting task, with some planning and careful thought you can provide enough flow for your corals to survive and even thrive. I haven’t found any one method that works best, but rather different equipment for different situations. As corals grow they change the flow patterns in the tank which may require that you make adjustments every six months or so.

Regards,
Kevin

[charlie]

Great tip Kevin!! The last paragraph is the one that I think most people don't even think about. I noticed it in my tank. If you hadn't said anything to me about 6 months ago, I know I wouldn't have given it a second thought. I have had to make a couple of adjustments. Ah well, it's just part of the ever continuing game of reefkeeping. It makes life interesting!!

[vtec si]

This is very true! I noticed that every 6 to 8 months I have to change my wave maker a little. If I don't then the corals growth slows and I can't frag anything.

Martin

Great thread Kevin.

[dougc]

With 2 Tunze 6100s and 1200 gph from my return pumps, I still think sometimes that I could use more circulation, at least for the purpose of preventing detritus from settling in the tank. Having some lower flow areas is necessary if you want to keep corals that don't like excessive movement, like frogspawns, elegance, and other lagoonal creatures.

Note what happens to an acro growing in the direct path of a Stream. Definite lean to the right with the prevailing wind.

[Poseidon]

Great Info...

Since I added a stream last week I am anxious to see a difference in growth.