Aqueon says change filter once a month.. isn't this bad?

[seakaurora]

I've been following Aqueon's instructions to change the replaceable filter "cartridge" once a month, and recently I had a fish die.. in my research I read about how it is bad to replace the filter as you loose the beneficial bacteria. So why does Aqueon say to do this once a month? Should I follow the instructions or do as others do and clean the cartridge in current fish tank water (after removing from tank) and then put it back in and do this until cartridge really starts to look worn then toss? which is better? I know Aqueon probably just wants to sell cartridges but if it's harmful to the fish shouldn't there be some sort of warning about this?

 

[V227]

Don't change out the filter cartridge until the polyfiber begins to unravel. Rinse the cartridge in used tank water every few weeks. It might be neccessary to rub some of the accumulated gunk off the face of the cartridge w/hand every once in a while.
Of course the filter manufacturer wants rapid fire cartridge change outs. $$$ for them.
If there is room in the filter box consider stuffing Fluval / Aqua Clear replacement foam sponges in there. Age them, then toss the filter cartridge. Sponges last for years. Just squeeze them out to clean.