Will increasing overflow drainpipe size by 1/2" or more, improve anything???

[Billy Danz]

I have a DSA 105 reef that came standard with a Durso drain set-up. Looking to convert to a Herbie system. The two drain pipes are 1-1/4" that are reduced to 1" at the drain bulkheads. I want to increase the siphon drain pipe size to 1-1/2" (reduced to 1" at the bulkhead) and increase the emergency drain pipe size to 2" (also reduced down to 1" at the bulkhead) So my question is this: Will increasing the pipes to these sizes give me any added benefits or could there be possible problems I'm overlooking, or will there be nothing to gain by doing this???? Thanks.

 

[A sea K]

My non engineer best guess without running any calculations would be quite simply that your drain will only flow what the smallest restriction will allow. So basically upsizing your pipe to a larger diameter with a 1" bulkhead will do little to improve flow. There is however an advantage when using upsize pipe, any valves you use will maintain full flow where as a 1" valve will have a much smaller opening than a 1" pipe and further restrict flow. I did upsize my siphon drain (it is valve controlled) on my Herbie but not on the emergency as it has no valve just an open pipe