Proper Circulation - 500 Gallon Plywood

[ShanerBock888]

I just finished buying all the materials to build my 500 gallon plywood tank, and before I start construction I just wanted to get some feedback on my setup in terms of circulation. I've never had a tank this size and I can't seem to find any definitive guide to keeping water properly circulated.

The tank will be about 4' wide, 7' long, and 3' deep. It will have 2 overflows and 2 returns. As of right now, my plan is to have them on the same end of the tank, with the returns below the overflows and about 8 inches above the substrate. Heaters will be in the sump below the tank, and I plan on putting a bubble wall on the end of the tank opposite the plumbing. My thinking is that the pumps will push the warm filtered water across the tank, where the warmth of the water and the bubbles will send it to the top, where it will flow back to the side with the plumbing.

I just want to know if this setup will circulate the tank properly or if there's anything else I should do or change. Should I add a powerhead or move an overflow or return? Any advice or changes I should make? Thanks!

 

[Niners4952]

Depends on the fish you have, me personally just built a 600 plywood and I have 3 2" drains at the top on 1 end and 2 1.5" returns on the side to get my flow. I may add wave makers at the opposite end if I feel its needed.

 

[Danh]

I had two 750 gph pumps sitting in the bottom of my 480g with 7000gph going through the sump. I really don't believe that it was overkill.

 

[fishguy306]

If you are doing a sump do not do your returns that low in the tank. If the power cuts out they will start draining water from the tank. Even with check valves it is risky. Check valves can and often do fail.

 

[carbene]

i have about 3000gph going through my sump on my 480 and a jebao wp60 to turn it into a whirlpool. my return is set at 3/4- 1" submerged.

 

[millerkid519]

If you are doing a sump do not do your returns that low in the tank. If the power cuts out they will start draining water from the tank. Even with check valves it is risky. Check valves can and often do fail.

You drill a syphon break hole at the top of the return right under the water line

 

[fishguy306]

That works if you run your returns over the top and down to the bottom, I was under the impression he would go through the back of the tank. I guess in my mind part of the appeal of plywood is being able to customize, I wouldn't want to go over the top if I had a return that low.

That said drilling a hole still makes me nervous. It is more of an issue on the reef side of things but I have seen those holes clog up.

 

[Cu455]

Put your return pipes on the opposite side of the overflow. The bubble wall is not needed. What kind of fish? If you want some good water movement look into the Jebao crossflow.

 

[ShanerBock888]

If you are doing a sump do not do your returns that low in the tank. If the power cuts out they will start draining water from the tank. Even with check valves it is risky. Check valves can and often do fail.

My plan is to run the return hose up above the water level and then down through the side of the tank. It's going to be built in to the wall so this won't be visible. As I understand it, the tank won't drain down to the level of the return this way.

Put your return pipes on the opposite side of the overflow. The bubble wall is not needed. What kind of fish? If you want some good water movement look into the Jebao crossflow.

I'll be keeping a TSN and RTCxTSN for now, so I want decent flow. I have looked at the crossflow and am consisdering it. Down the road these guys will be moved to a pond, but I'm not sure what will take their place when that happens.

 

[pacu mom]

If you want "decent flow" as in a swift river current, consider using a venturi return nozzle.

http://www.poolzoom.com/inlet-fitting-return-line-venturi-infusion-black.html


On this web page, they say you can create a river rapids by turning it 90 degrees and adjusting the V fittings.
http://www.eztestpools.com/infusion-v-fitting-return-line-pool-spa-fittings/

We have one in our 8' 300 gallon tank. It is the return for our mechanical filtration run with a Reeflo Hammerhead pump. The return is on the far right of the tank. The current hits the left wall and heads back to the right. Because the nozzle can be turned in any direction, and the V fittings can be adjusted, you have a lot of options with the direction of the flow. Here's video during a water change when we are refilling the tank. It shows the water movement in the tank.