Mak 4 and 1 1/2" stand pipe question

[Delphinus]

It "computes" just fine, Darren ... there are merely other variables at play that just aren't identified. 1.5" stockman standpipe, 1" pipe to the sump, two 90 degree bends. Cannot keep up with a Mak4 at about 3' or 4' head.

It could be the teeth itself of the overflow, the length of the standpipe (height), or it could be that the first 90 degree bend is in the bulkhead itself. Wasn't interested enough to figure out the exact reason, but hey if you're interested enough and want to find out, you're more than welcome to come out anytime, Darren.

But, it's not like there's an issue here for me, this works out just fine. I don't WANT a full MAK4 kind of turnover from my sump -- I don't want a microbubble phenomenon. I currently run the MAK4 at about 40% as the sump return, the rest drives the skimmer. It's actually working out, at least for the moment, seemingly just fine...