I was very pleased with the EHEIM Ecco canister filter. It cleared up my tank’s water in under a day after installing it and keeps the water sparkling clean. I do disagree with the instruction manual though, if you chose to use carbon you should place it in the filter right after the coarse filter pad though and if required in a media bag on the bottom of the middle basket. I don’t recommend replacing any of the biological media until it gets clogged though, you should clean it monthly, too. Overall I think it is a great filter, especially since the multifunction handle actually self primes the pump, something some filters say they do but can’t. I also like the fact that it is so easy to open and clean. I think this is a wonderful filter and recommend it to anyone who needs better filtration than a simple HOB filter can.