Hi, I have a problem, the chiller measures a temperature of 81F and when it turns on it drops to 77F, but in 5 minutes it measures 81 again and then turns on and drops to 77 which turns off again, and so on, a loop. A curious fact is that the temperature inside the fish tank does not vary within that period as measured by the fish tank thermostat. The chiller is activeaqua AACH25 1/4hp.