Return plumbing size

[DCR]

What other options do I have to remove the loc-lines? What else would I put into the bulkhead for the flow? On a side note, wonder why they don't make 1" locline

I think that getting 2x500 gph returns would be more than adequate for a 220 gal tank, so I am not suggesting you change anything. Going with just the 1" bulkhead will maximize the flow. Adding the loclines or other return ends increases the velocity and turbulence at the expense of flow. I think it is more cost effective to use powerheads for that rather than the return pump to create internal mixing. Other than redundancy, I don't think it makes much sense to run two COR20's. You won't get much additional flow with the second pump due to the restricted piping and you are just using a lot of power for small incremental gains in return flow.

 

[Mark Gray]

Here's what I have decided to do, I have 2 Cor 15s for my 90 gallon. I am going to plumb them both into a manifold then to the tank. This way I can run a chiller and a carbon reactor or something else, and it one would fail the tank could still run on one pump

 

[drtrash]

If you are running 1" bulkheads, what is attached in tank? Threaded 45?