Waterflow problem

[Sunshine]

We have a 90 gal. tank and a 30 gal. sump/fuge. Every time we do a water change and start the pump back up, the flow gets messed up. We have a 1200 pump. The tank has a mega-flow. We have 3/4 inch tubing from the pump to the tank. And 3/4 from the tank to the sump which has a ball valve that we turned back some, but still couldn't get it right so we put a hose clamp on the tubing and adjusted it that way. It all flows good till we turn the pump off to do water changes. The overflow part is always low and we get that waterfall effect. We fill it up, and it goes low again within minutes. Why is it doing this ?

[jeremyreef]

what brand is it? cant really tell by just the 1200. does the overflow pluming have a loose connection?

[marinelife]

Maybe a larger hose on the pipe to the sump.

[Sunshine]

It's a mag drive from Foster and Smith Aquatics. No loose connections.

[TechGuy40]

First off, you don't want a ball valve on your drain line. Snails, gunk, and crap will clog it and overflow your tank in a few minutes.

Are you using the plumbing kit made for your tank? Lots of people make their own, and its a mess. The pump does 1200GPH? Should be plenty for a 90 with a built in overflow. Got a picture? Our 75 has a built in overflow, with a 1000GPH return pump and we get an ocasional gurgle, but nothing too bad.

[Sunshine]

[marinelife]

remove the black hose, go bigger, then add a valve to the air hole so you can adjust it. Once adjusted the overflow should always work.

[Sunshine]

That little air thing on top of the overflow ?

[marinelife]

yeah to much or to little air will cause problems.

[Sunshine]

So, take all the tubing and ball valve off the drain and put bigger tubing ? Than put a valve on the air line ? The tank and overflow kit was on sale when we bought it from Petland, they were going out of business, the regular air elbow was missing from the box, so we bought an elbow, drilled a hole and did it the way it is now.