Declan
Fishaholic
Ceramic media?There's no need to completely change any sponges ( but if you are treating with meds then do remove the black carbon one as it will stop the meds from working by removing them ) . They last years and despite what the packaging tells you, unless a sponge is literally falling apart there is no need to change it. If you take all the sponges out and replace them you will destroy the biological cycle in the tank. The company only tells you to change the sponges as they are relying on you to know nothing and simply go out and buy more each month. It's a money ploy and nowt more.
Just take out the carbon ( black ) one and replace it with either another white sponge, or if they will fit, some ceramic media ( more surface area for bacteria ) . You also don't need to rinse your sponges every week. Only when the flow starts to slow a bit on the filter, then you should wash one of the sponges like you do currently in a bucket of used tankwater.
Sorry thats a real noob question...
D.