Or a cheap pool heater? For 755 gallons my new pond am building for my grandfather it's going to look really nice but the fish he wants are tropical so were looking for a heater. Am going by 3 watts per gallon then + 300 since it's outside. 2,265WATTS we need. Were looking for around 84-86F. Am in Cali so It doesn't freeze over and get extremely cold (LA). Wrre planning on only putting in about 4 Silver Aro's. Thanks.