There is the reason right there.

I was running 1.5" all the way to the sump. no 90 degree bends. one 45 and that was it.

In effect you are running a 1" drain. I had a 1.25 restriction(didn't need it) but the entire plumb was 1.5".

hth

Hey, YOU were the one who said it didn't compute, not me .... :razz:

I didn't see the 1" reduction in line size Tony.

Darren, what size air hole did you use for that AM3k using the durso?

I've got two 2" Durso's reduced to 1.5" I think it can handle flow :eek: but on later reading plumbing above 1.5" does not have to be enlarged oh well. Just throwing that out there

(Don't they teach ya to read in school???? :razz: :wink: :biggrin: )

I wanted to go with a bigger pipe all the way to the sump, but there were basically two impediments: one, the bulkhead has a built-in 90 degree so I'd have to cut it to get it out and replace it. Two, and I guess more important, the bottom glass of the tank is tempered so I can't drill a hole for a larger bulkhead. So 1" I am stuck with.

At the rate the ritteri is growing, I'll need a bigger tank soon enough, so there's no sense in putting more work into this one in the meantime. :lol: