Bulkhead Size?

[Kasey Grohowski]

I have a 3645 gph return pump on my 220 gallon reef tank and wondering what size bulkhead and return line would be best.

 

[Gablami]

If your goal is to maximize your return flow, I would keep the return plumbing, and bulkhead, the same size as your return pump output diameter. Most people don’t do this, and at some point it is downsized. This will reduce your flow somewhat, but is often more practical and appealing.

 

[laverda]

I agree, however there are other things to consider. You really do not need that much flow through your sump and your skimmer will not be able to process that much water. Pumping that much water requires a lot of electricity 25/7 which may or may not matter to you. It can also produce a fair bit of heat as well. I like a lot of flow in my sump but would only aim for 1100-1500 GPH through your sump. There really is no reason for more than that.
In addition I doubt the overflow can handle that much flow. I know my 240 overflow and sump could not handle it. On my current 300 the overflow can handle it, but the return section of my 90 gallon sump will run dry even after being modified for more flow.
Also consider how you want your return to be set up. I am guessing your pump has either 2” or 1,5 “ output if it flows that much. That makes for a pretty big return line going into the tank. Keeping the return full size as far as possible then splitting with y fitting to 2 or more smaller returns can still allow full flow with minimal restrictions. Try to avoid hard 90 degree elbows and keep the number of fittings to a minimum for the most flow.

 

[Kasey Grohowski]

I agree, however there are other things to consider. You really do not need that much flow through your sump and your skimmer will not be able to process that much water. Pumping that much water requires a lot of electricity 25/7 which may or may not matter to you. It can also produce a fair bit of heat as well. I like a lot of flow in my sump but would only aim for 1100-1500 GPH through your sump. There really is no reason for more than that.
In addition I doubt the overflow can handle that much flow. I know my 240 overflow and sump could not handle it. On my current 300 the overflow can handle it, but the return section of my 90 gallon sump will run dry even after being modified for more flow.
Also consider how you want your return to be set up. I am guessing your pump has either 2” or 1,5 “ output if it flows that much. That makes for a pretty big return line going into the tank. Keeping the return full size as far as possible then splitting with y fitting to 2 or more smaller returns can still allow full flow with minimal restrictions. Try to avoid hard 90 degree elbows and keep the number of fittings to a minimum for the most flow.

No overflow, my tank will be drilled.