I hope I don't have to keep the sponges in place. After my Ich problem, Once I get tank settled down and cleaned up again I would like to be able to remove all but the 1 sponge infront of the bulkhead. I am going to try removing them 1 by 1 until I get down to zero if possible and just use the LR piled up around the bulkhead. I have to admit 1 thing about the sponges it cleared up my sandstorm in a matter of no time with sponges catching the debris.