Actually, you don't need to replace the filter floss/pads except for every couple months. It will get grungy and look gross, but they only need to be tossed when they are falling apart. The lfs
and the manufactur will tell you to replace them at every water change, but remember, everytime you replace a filter pad, they are making money. It's the same thing with chemicals. If you go to the lfs
and tell them you have high ammonia, they will tell you to use Ammo lock or Prime. This will only mask the problem temporarily. Water changes can do the same thing, and it's cheaper. You won't be subjecting the fish to any chemicals. If you get a cloudy tank, same thing. They will sell you chemicals when all you need to do is water changes, keep the lights off in the tank for a couple days and it will go away.
The water straight from the tap, when rinsed on the pads kills the bacteria that has formed on the pads. When it is swished around in used tank water or even dechlorinated water, the bacteria isn't killed off.