Good is just Dennerle

One problem, however, there at least I think that's the suckers are too weak, the filter slides off and on from the rear wall even if it is clean and algae free.

A little tip on the first mall clean this filter is essential to ensure that when dismantle the small black cap at the bottom of the pump does not slip or Flasch sitting when the filter is then put back together SUGT they no longer feel right.