As well, the filter bacteria in cooler systems do not function well, and ammonia problems may result. Undergravel filter 2. Partial waterchanges weekly 3. Temperature 74 degrees or warmer 5. Turbulence and high aeration are a must.
Silent tanks spell death.
Salt at the first sign of trouble. Filtrate with an Undergravel plate driven by a single powerhead. Make sure the powerhead runs Venturi-style, which aerates well. Make sure the pH is 'buffered' to neutral, there are chemicals for this. One such compound which is readily available and cheap is SeaChem's Neutral Regulator.