I am getting ready to place an order from one of the fish catalogs. I found that they now have BioMax for AquaClear filters which is what I have. Currently I use a sponge and ammo-carb in a media bag for each of the tanks. Been using this way for 14 months with no problems with my tanks. Still have all the original fish for both tanks along with many newer guppies. Question I have is does the BioMax have to be replaced every month, two months or is it like the sponge that I can rinse in aquarium water thoroughly and it lasts a long time. I live in a rural area with very limited aquarium supplies and no one sells the BioMax. So if I am going to change over to it, I want it to last awhile so I either don't have to make special trips into Green Bay (quarter tank of gas) or order all the time.