Latley when i clean out both my HOB and Canister filters for my 125gal. There are baby snails, i use to have plants but i got rid of them all and i always use to check them for snails before i put them in the tank. are they harmful, They are mostly in my canister filter which is and XP3 and very few on the biowheels on the back of the tank. They are nowhere to be seen in the tank. Are they harmful or anything? Any solutions?