Tank is 10 degrees warmer than the house

Cleaning the pumps unfortunately didn't make a difference. However, the big Seio pumps were actually closed down on their intakes because the amount of current generated when were wide open was too much. So I replaced these pumps with the smallest pumps from Seio and the tank dropped 5 degrees I have not found a found yet but will eventually add one above the tank to try and gain the last 5 degrees drop. Thanks everyone for all your help and suggestions.