I have 4 small tanks with Aqueon built in filters (the tanks are those "betta bows" kits with filter and light) and bigger tank (resale so not sure of brands) bigger tank with filter that has canister hanging on a back of the tank. All filters take cartridges that need to be replaced every weeks. Question is, what is the best way to replace cartridge without risking disturbances in water chemistry balance? I've had some issues with cycling, then mini cycle.... Spent soooo much time and money (testing supplies and such) working sooo hard on getting things back on track don't want to take any chances with messing things up now that I seem to be finally getting somewhere. Should I somehow populate the new cartridge with bb from old one before putting it in? Sorry if that sounds dumb but I really don't know