Hi, today my Betta, Cole’s tank and a cloudy white film over the bottom of the tank. I had done a 40% water change yesterday. Tested today, ph 7, Ammonia .25, nitrate 20, and nitrite 0. He also has been hiding in his cave a lot the past week. The only live item in the tank is 2 small moss balls that have been there since February. Any ideas what is causing this?