I've currently got a 11 year old single speed pump and I want to replace it with a variable speed pump to help save money on electricity. Pool is in ground 35000 gallons with 1.5 inch pipe. Curren filter maximum flow is 62GPM and current pump is 3450rpm at 1 HP. From what I can tell I need a pump that won't exceed 60 gpm. A lot of the pumps I see exceed that. Do these pumps have modifiable speeds so that I can set 4 speeds that won't exceed that rate? Thanks in advance. Any particular recommendations?