2 return pumps into 1 line??????

[Mugg1977]

In designing my 140 FOWLR, I have determined that I want 1 corner overflow. I can get a custom from the LFS that has 3 bulkheads (will discuss the size of the bulkheads with them later). My plan is to use 2 sumps (1 fuge and 1 actual sump) that will be tied together at the return chambers to prevent any overflows. I would like to utilize 2 return pumps for redundancy (I travel a lot and want to make this easy on the wife).

My question is this - If I stay with 3 bulkheads in the overflow, 2 drain (1 for each sump) and 1 return and I tie the 2 sump return chambers together with 1-1/2" or 2" pvc, can I use 2 return pumps in parallel that manifold into 1 return line? I am looking for about 3-4x from total from the pumps combined (+/- 700gph).

 

[Scooterman]

One issue you would need to consider if you loose one pump the other would just recirculate through the other, so you'd need to consider maybe using check valves. Now if you plumbed them separately that would be eliminated. I would also consider drainage, more is better, if they are all 1" drains I'd consider using them all as drains & just go over the top with the returns. One thing I noticed with my last two tanks, although I feel you don't need high flow through the sumps, the overflows work better with more flow, that is one reason why I'd consider bumping the flow rate slightly higher, like 1200gph pumps, with head loss It will be tuned down some anyways.

 

[Mugg1977]

Scooterman -

Thanks so much for your help and replies!

I didn't think about the check valves. I will probably have to use 2 over the top returns (don't trust check valves in salt), as I definitely want to have 2 pumps (still will tie the sumps together).

Thanks again.

 

[Scooterman]

Well I did do this while switching out pumps, ran them both, one was 1500gph & the other was 900gph, It seemed to work fine until I turned off one, then it just recirculated. I don't know what the long term affects of having one pump larger volume than the other but it did work. I really don't see the need to have redundant pumps even if both were the same, IMO they run well for a long time, two things could cause failures. If your running a magnetic pump, then restart could be an issue during a power outage & as with any pump, from time to time it needs a through cleaning & inspection.

 

[dnjan]

I agree with having two overflows. I think the redundancy of a second overflow makes lots of sense for any tank in the 50-gal range and larger.

I also would not run two return pumps into the same return. If you want redundancy, go for full redundancy.

And don't forget the shut-off valves (full-flow ball valves) and true unions between the pump and the return outlet. That way you can take one pump out of service for maintenance/replacement while the other still provides at least some flow.