Filter Overflowing - Help Please!

[schmee]

Hi i need some help. My filter is a trickle filter, i noticed it had filled up rather a lot as the water level of the tank had dropped a few days ago. Now there is water running down the back and side of the tank (on the inside!) as the filter is so overflowing. i've had a look inside the filter but i have no idea what the problem might be. Water is flowing out of the filter in the normal way fine as well, it's not blocked as far as i can see.
Any ideas??

 

[BigIan]

have you cleaned the media recently? if so that could be restricting flow.

 

[schmee]

have you cleaned the media recently? if so that could be restricting flow.

Nope. i haven't touched the filter and the strange thing is the flow doesn't seem restricted, yet water is building up. Any other ideas?

 

[OldMan47]

If you are having water build up in your filter, there is something restricting return flow. To me that means it is time for a good cleaning of the filter media. Even if it still looks clean, it is not passing enough water, as you have noted with the level rise.