When should I buy new filter pads?
Hi I've got a fluval box, internal filter (for 63l uk tank - now very much fully stocked) which has two pads inside and a third skinny pad in middle (which is/was white so it's not a carbon pad) I don't know much else about it cos it came with the tank. I rinse one pad at a time when doing changes in tank water. They're looking quite brown now and I've had them since getting tank (running about 6 months). Just wondering if i need to replace pads yet? Maybe one at a time or just leave.