Water flow rate for corals

RibbonFish · Feb 11, 2014

Hi,

I am learning about coral. Some just died again.

My return pump for sump is 700 GPH, tank is 40 Gallon, only live rock, not sand. Only soft coral, and flower anemone. Yesterday, flow anemone and one Xenia coral died.

I have a wave maker of 850 GPH in my tank .

My questions are:
1. Everytime, when I turn the wave maker on, the water will not be crystal clear. I know strong water flow will stir the tank and it will kill the living. But is it my case? Is my water flow too strong?

So, the pump will give about 700 GPH and the wave maker will give 850 GPH. If I only have the pump on, will 700 GPH be good for the corals? If yes, I will just move the wave maker.

Thanks

Reefing Madness · Feb 13, 2014

Your return pump is normally not used a a flow counter, as its just being used for a return, and can't be restricted in any way. So you 850gph wavemaker should be on all the time.
What do you mean when I turn it on?? you should leave it on, the tank will clear up.
Your water params would be a good start, to know whats happening to your corals.
Temp 76-79
Ammonia-0
Nitrites-0
Nitrates- under 10
Phosphates under .05
SG 1.025-1.027
Cal- 380-420
Alk- 7-12dKH
Mag- 1250-1350 (can be higher, some run it at 1600)
Those numbers are where you should be running things, if any of those are way off, that'll kill coral.

Palting · Feb 13, 2014

If you question is why are your corals dying, then we need more information about your system. You need to post tankndimensions and age, filtration system, lights, parameters, etc.

If your question is about flow for corals, I can give you the general recommendations.
I'll talk about total flow, so lets define total flow as the effective gph of your return plus all the gph of all your powerheads.
Flow for corals depends on the coral. For softies, total flow should be about 10X-20X DT volume. For LPS, 20X-30X is preferred. SPS like a lot of flow, upwards of 30X DT volume. For mixed coral, the key is to have areas of different flow in the tank.
Aside from total flow, it's also very important to have ALL the water moving. Meaning, there should be no dead spots. Detritus can accumulate in dead spots, and this can give rise to a ton od problems later.
Random, chaotic flow is also preferred. Flow bouncing off walls, off the rocks, and off each other.