Just a quick question.
I have a fluval 304 external and it's well matured, about 4 months or so on my tank.
It gets cleaned weekly... However the water inside the canister is brown, when my tank is clear / small tint of brown.
Am I supose to empty the filter water and fill it with tank water when I clean it?
I've always just left it thinking it's the 'benefical bacteria' that are browning it....
Any ideas? Cheers.
Oh, and water is tested often and nothing wrong with it.