Skimmer fills up when I cut the sump pump off? Need help

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.


Aquarium Advice Apprentice
Sep 10, 2021

I can't figure this out but I'm sure others have had the same problem......
this is a new tank and I'm a rookie at this....

I've got a 25g IM Fusion Lagoon with the mighty jet pump that comes with it in the middle sump chamber.....a new Icecap Nano K1 skimmer in the #2 chamber on one side......separate from the main pump.

the skimmer can be set just fine, with foam low in the's not really making anything now, I really have it running open to start the break-in process.

My problem is when I cut the mighty jet pump off for feeding, my Icecap skimmer immediately starts filling with water. Its sitting about 8" down into the #2 chamber. It fills the cup 1/2 way up real quick before I have to unplug the skimmer.....not sure if it would stop filling or overflow it. It does this every time I cut that main pump off for feeding.

What's the solution? This must have something to do with the pump pressures I'm guessing? when I cut that main pump off I don't see any difference in the sump water level or anything like that......

Have I got to put these on a separate switch or timer and cut them off together? or am I setup wrong?

I haven't seen this problem mentioned anywhere before......:(:confused:
Top Bottom