Pre-filter sponge on filter intake?

[TheWolfman]

Sounds like you need a corser sponge or you need to be cleaning it more often. I run a intake sponge on a ac70 and don’t have any issues with clogging.

 

[Big Jay]

The only reason you use a prefilter is to prevent sucking fry. If you use it to prevent sucking sand, your filter suction power is too strong. The one filter I know powerful enough to suck sand is AC500, but it has a valve that allows you to dial it down.

This is the only time I've used it myself. It works as advertised for that purpose. However, like you found out, it collects quite a bit of excrement.