Where's my flow going?

[SwiftStorm]

I need a little advice. I have a 75 with a trigger 26 underneath. The tank is a cheapo from Petco so I used an Eshopps PF-800 overflow. I was under the assumption this would give me 800 gph. I'm using a COR15 and cannot get it over 35% without the return section in my sump to slowly drain out. I understand 500 gph isn't bad, but I would like more.

I used 1" PVC plumbing for the return. I only have 2 90s plumbed in with some unions. My return is 3/4" PVC with 4 90s and a silicon tube sweeping from pump to PVC.

No air bubbles in U tube. Overflow teeth have zero build up on them (try to keep them clean). I even removed the foam cylinder eshopps places around standpipe.

Thank you

 

[dadnjesse]

You should try and avoid any 90 degree fittings, that could be the problem.

 

[Lightspeed]

@SwiftStorm Said:

"I need a little advice. I have a 75 with a trigger 26 underneath. The tank is a cheapo from Petco so I used an Eshopps PF-800 overflow. I was under the assumption this would give me 800 gph. I'm using a COR15 and cannot get it over 35% without the return section in my sump to slowly drain out. I understand 500 gph isn't bad, but I would like more.

I used 1" PVC plumbing for the return. I only have 2 90s plumbed in with some unions. My return is 3/4" PVC with 4 90s and a silicon tube sweeping from pump to PVC.

No air bubbles in U tube. Overflow teeth have zero build up on them (try to keep them clean). I even removed the foam cylinder "

A little cofused by your statement regarding 1" return and also 3/4 return.
I will read it as 1" overflow and 3/4" return.
Looking at your pic the 1" overfow valve is wide open, you stated you cant run the Neptune more than 35% without emptying the return box, so it simple if you want to increase sump turnover you are going to need to increase the supply to the return pump, either an additional overfow or increase the diameter of your overflow line to 1. 1/4", if you do that you may find the next choke point being the U tube siphon into your overflow box, so bottom line, bigger overflow and larger overflow plumbing.
Probably not the answer you want, but its obvious the overflow supply is you choke point.
As suggested by @dadnjesse 90 degree elbows are a last resort, avoid if you can, as well as locline.

 

[X-37B]

For a 75 I would only want 150-200gph through my sump.
I run 2-300 through my 40 breeder on my 120.

 

[IamChrismWard]

Try putting a second "U" pipe from the Overflow inside your tank to the exterior part of the Overflow, it looks like the one you have is 3/4 in and there's not a whole lot of flow through that when the drop is only three or four inches. I havd to do that on a tank I had 10 years ago, like stated earlier try to get rid of some of those 90s you want the water coming off that overflow into the sump as resistant free as possible. I've used inch and a quarter flex pipe on returns in the past you could look into that as well