Important December Statistics

December '12 was a pretty frigid month.  I'll post the averages once they are available from the National Weather Service.  My pond was affected as follows:

Temperature: 40 F
PH - 6.0 or less (drop from previous measurement)
NH3 - 0.25 ppm (drop from previous measurement)
NO2 - 0 ppm (stable)
NO3 - 80 ppm (stable)

My fish are now hibernating and eating much less. I assume the stable nitrates mean there is enough N+ for the plants. Added garden lime to sump tank to pull down PH (12 tbsp of Garden Lime by Espoma). In the past this has not been traditionally helpful. Added 5 gallons of water through a chlorine filter. I may try removing five gallons and then adding five gallons of fresh water to assist PH in future.