So I bought a new return pump...

[dippin61]

Well I finally gave in and bought a new return pump. Some of you may know that I'm a huge advocate of slow/low flow through the sump. For the past couple of years, I've been using a MJ1200 as my return pump. Works awesome, and lets the skimmer do it's job. My only problem with it was, that my U-tube would always get air trapped in it, because the flow wasnt enough, so I found myself resetting the U-tube once a week or so. Kind of a pain in the butt. Gotta turn off the return, pull the U-tube out etc etc.

So I didnt really want to spend much on a fancy return pump, so I ended up getting a Sea Line SL-6530 which is rated at 430 gph. (Great pump BTW. Its quite silent, more so then the MJ1200 I was running.) I figured my regular 'ol U-tube overflow with 1" drain would be able to handle it no problem. Especially with 4 ft of head. I always thought a U-tube overflow with 1" drain could handle about 600gph.

Problem.

First off, the overflow couldnt handle the return pump. I actually had to add another U-tube I had laying around just to keep up with it. And that added even more problems. Flushing. To fix the problem temporily I added another hole to my stockman. That seems to have helped the flushing a bit. Still makes noise, but for now I can live with it. But the overflow still doesnt look like it can handle it. The water level inside the overflow box, doesnt go down as far as it used to, and has stopped skimming the top of the water. So now I have scum on the top.

So, where do I go from here? Should I try and plumb in a ball valve on the return and have the excess drain back into the sump, (problem is I run 5/8" vinyl tubing. Do they make 5/8" PVC, or 5/8" ball valves?) or do I just bore out the overflow drain to handle like a 1.5" drain?

[GreenSarco]

The cheapest way to do it would be to tee off the pump, but your overflow should be able to handle the pump. Usually a U-tube can handle up to 600 gph. You can also get a high flow overflow such as the ones made by cpr.

[rcypert]

go back to the maxi and rig a hole in the u tube to suck out the air. hook the airline to the maxi and it will draw the bubble that kept building up out.

[aquarius77]

Then hes blowin micro bubbles back into his display.

[RocketEngineer]

Originally posted by aquarius77
Then hes blowin micro bubbles back into his display.

He would only blow a bubble into the tank if one got stuck in the U-tube. Otherwise he would just be pumping water from the overflow. I would rather have a bubble every now and again then risk a flood.

[Sepeku]

Originally posted by RocketEngineer
He would only blow a bubble into the tank if one got stuck in the U-tube. Otherwise he would just be pumping water from the overflow. I would rather have a bubble every now and again then risk a flood.

Or, for completeness, there is a pin hole in the line bleeding it in.

[r00onmac]

your overflow should definitely handle it... i have a similar (if not the same) setup with two u-tubes and a 1" drain and it handles my quiet one 3000 (rated like 780 gph) at 3 feet of head... which according to the RC calc is 597 gph (pulling REALLY close to that 600gph max of a 1" drain)

all i had to do was put a silencer on the drain pipe and now it works great...

if i were you i would make sure my drain lines were clean including the u tube because buildup in there (even coraline) can cause a drop in drainage.

[dippin61]

everything is clean.. put in all new plumbing when the new pump went in..

its really strange.. accounting for the head, the pump shouldnt be rated for more then 500 gph...

really strange though.. might just go with a ball valve.