Wavemaker question

WvAquatics · Jan 29, 2020

So I am trying to decide what wave maker I need for a 40b. I don't plan on sps corals but don't want to be limited. So my real question is say I want 1200gph do I only need one 1200 gph or 2 600gph or even 2 1200 gph? Basically is the gph I am aiming for all I need in each pump or is it combined?

Ron Reefman · Jan 29, 2020

Do you have a sump? What is the return pump running at in gph?

With one 1200gph and no return pump you'll have roughly 30 turns in the tank (assuming it runs near full speed most of the time). If it ramps way down it isn't really a 1200gph pump, it's the average of the high and low gph rates. Two 1200gph pumps would be better and provide a much more random flow in both rates (due to two pumps ramping up and down) and in direction (due to two pumps working in different directions).

If you are just doing mostly soft corals and a few lps or sps, one should work OK. If you get to doing more lps and sps, you'll really want two. But this is just my opinion.

WvAquatics · Jan 29, 2020

I will have a sump and return pump is rated 300-1900 gph. Will that count as a wave maker also? I'm just trying to wrap my head around aspects of sump and wavemaker setup. So basically wavemaker if you want 1200 you need 1200gph. I honestly will only run about 800 to start but just would like ability to up for more corals in future. First build and want to do it right first time

Ron Reefman · Jan 29, 2020

Most people look at 'turnover rate'. This is the rate in gph of all your pumps (return pump and in tank pumps) divided by the number of gallons in just the DT. You need to take some kind of average of wavemakers. They say 1200gph, but that's at full speed. The ramp up and down so they aren't at 1200gph all the time. Say it goes from 1200gph down to 400gph. Then it's running at 800gph on average. That's the number you should use. Powerheads don't ramp so their rating is easy.

Example: return pump at 1000gph + 500gph wavemaker + 500gph powerhead = 2000gph divided by a 50g tank = 40 turns.

Soft corals are OK from 10 to 20 turns and more is OK.
Mixed corals are OK at 20 to 50 turns and OK with more.
SPS tanks are OK at 30 to 60 turns and some people go as high as 80 or more!

My tank is a new set up with old rock, coral & anemones from my old 40g tank. This tank is 90g and has just a return pump running at 2500gph (figuring in head loss). I have 4 outlets and that gives me 27 turns in a tank that is mostly zoas and Rock Flower Anemones. I may add a wavemaker at some point in the future as the tank matures.

WvAquatics · Jan 29, 2020

Ok until future when I can actually track the actual turnover on a wavemaker I'll figure it by how high I have it running. But the way you have yours is interesting. If I have my return pushing 800gph and one wavemaker pushing 800 then my total is 1600/40= 40gph correct? Also placement is it normal to place a wavemaker towards the top blowing down or bottom blowing up or middle ground?

Ron Reefman · Jan 29, 2020

Your calculations are correct. Just remember that the return pump will have some loss (maybe 50%) due to head pressure. The manufacturer should offer a chart to help you know the actual flow.

There are 2 issues to consider. Flow that pushes sand around, which is a problem. And over time the sand will settle and can take more flow without getting kicked up and blown around. Second is motion in the water at the water surface. Your tank will do most of it's gas exchange (CO2 out and oxygen into the water)at the water surface. Any motion there improves that gas exchange a lot. The water/air surface exchange is far more important that the oxygen that goes into the system due to the bubbles in the skimmer. Some reefers think the skimmer is enough, but it's not. There are different processes at work at the water surface than with bubbles in the skimmer.

Therefore, I'd try to get the return from the sump to make some water movement at the surface and have the wavemaker pump work the middle. Low enough so you get some flow at the sand, but not enough to push it around. You can see that the water surface in my tank is moving and not flat.