Question
I've got two 24 gallon tanks that both have the same filter inside of them but for some reason in one of them the sponges seem to be sort of "imploding" and I've got no idea what could be causing it to do this?
I've even inserted a replacement filter of the same model into this tank and the replacement has done the same implosion.
Both are tropical tanks.
Same model filter working as expected in another similar size tank
Answer
Water is pulled into the filters and exits via the pump and pipe; the waterflow in your setup is too powerful. This makes your filter sponges collapse.
The type of filters you're using in your setup is normally driven by an air pump where bubbles pull the water up and out of a vertical pipe.
There are a couple of ways to avoid this type of filter collapsing.
Clean the sponges more often.
Reduce the water flow.
Change your setup and use an air pump to drive the filters. You will still have to clean the filter sponges, but not as often.
Here is a picture of a common type of air driven filter for aquariums; it can be expanded with more filter sponges if needed.
Answered By - trond hansen