Hi, recently I've been given a 35 Gallon fish tank, and I just set it up last night. The water was clear last night but I had my heater on and I think it was pretty high to wake up with a really warm fish tank. There are no fish inside and it's cloudy! I don't know why it's Cloudy, and how to fix this. Is it possible that my heater made the water temporary cloudy? What causes cloudiness?