Aqua Clear 70

[severum mama]

I totally agree, but I can see where you are coming from with regards to removing tannins. You do need to replace carbon regularly for this purpose.

 

[Ulan]

Yeah I've read a decent amount on the debate over carbon, and regardless of which side you're on it seems there's at least agreement that it shouldn't need to be changed as often as the manufacturers claim.

Interestingly, in the manual of my Eheim (canister) filters, the manufacturer recommends removing the carbon after filter has been running for a while .