Hello I’m new to the forum I have a 75 gallon tank I have two sponge filters a UV light I have about 20 corys in there a sand substrate I have what somebody told me is Bio film I cannot get rid of this stuff no matter what I do does anybody have any suggestions on what I can do the tank is 6 months old ,well water ,there are snail in there all my shrimp died 🥲🐟I am so sad over this I have a back injury so it’s very hard for me to work on the tank I really love my fish but I think I may have to get rid of them if I can’t fixes thank you’ll