Filter Emptying Back Compartment (help!)

[IridescentOrchid]

Hi, I have a MarineLand 5 Gallon Portrait Glass LED Aquarium Kit and have had it for a while with no issue. Recently though, whenever I turn the filter on (which is in a separated compartment in the back) the front of the tank fills up, while the back empties. The water evens out whenever I turn the filter off, but I don't want to have to leave it off for longer than it has been, and turning it on and off repeatedly to try and filter the water seems like a waste. Has anyone else had this issue? Is my filter broken? It's worked perfectly before, I don't know what has happened to it.

 

[IridescentOrchid]

(The hyperlinks appeared on their own after posting the thread, I don't use the equipment in either link)

 

[kallililly1973]

have u cleaned it since owning it. U shouldnt have tro turn your filter off at aly time it should always stay running. Do you have pics?

 

[Jonmott]

Your filter media might be clogged, have you cleaned it recently?

 

[Skavatar]

its a built in filter, check to make sure its not clogged up.

 

[JayH]

Whenever the sump level is significantly lower than the tank level, it's an indication the media is blocking water flow and not letting water into the sump at the same rate as the pump is returning it to the tank. Check that the inlets aren't physically blocked. If they aren't, then it's probably time to clean or change at least the filter media the water first hits.