Any reason do have 2 returns.
 

I am working on another 40b build and am getting ready to drill it. On my previous build I drilled 2 returns, but was thinking that 1 would be just fine. Other than having more flow options, is there any advantage to having 2 returns instead of just 1?

Slower flow from both returns might make a sand bed stay in place.

If I was doing the overflow in the middle, I would do a return on each side of it....overflow in the corner, one return on the opposite side.

I don't see any reason for it. If you want flow from more than one output just add a manifold.

Honestly, there is no reason for multiple return outlets. Circulation pump are for this purpose to give flow and movements to the tank. The return allows for "Filter" water to be return and your circulation pump to mix things up. and the cycle starts over again

Thank you all for the responses. I think I am going to just do 1 return. This will simplify the plumbing. I am not worried about the return blowing sand all over since most of the flow in the tank is provided by the wave makers NOT the return.

For that size tank I’d do one to cut costs.

The tank I just had built I went with two. The tank is 60x36x24 with an internal Modular Marine 36” overflow box centered on the back panel.. I wanted the tank to look symmetrical so I went with one on each side...strictly for looks.

I heard somewhere that people use two as a redundancy - just in case one gets blocked for whatever reason.

:fish1: What is the cost difference between one or two returns in a tank that size? I would do two, as it would give better water movement in the tank. :fish1:

Maybe $30-$60 in fittings/bulkheads/loc-line/pipe/etc. Never said it would be a huge savings, but to some people money is money...

With a 40B only one is needed, most the flow should be from the wavemakers.

I ended up going with just 1 return and I am happy with that decision so far.