My L-14 and L091 which are in a 50 gallon have been chewing on the sponge of the sand filter. I think this is man made sponge and wonder if it is harmful to them? i don't see any ill effects and this has been going on for about three weeks now. Don't know if they are consumiong the sponge or is it just breaking apart and getting sucked in the big Aqua clear 500.
