Pool pumps are sized to a 8 hour pump cycle. This is because they generally are run during the day such as not to cause noise and problems with neighbors. The rule is the water should be turned over, that is pass through the filter, once in a 24 hour period.
The system is more efficient if the water is pumped slower over a longer period. All else equal, by pumping over a 24 hour period with 1/3 third the flow rate 1/3 the power will be used.
I also have a 40K gallon pool. I use two pumps. One, 3HP is used to run the pool cleaner when I want to. The other is a two speed that I have wired for low speed at 1/3 HP. I run it during the week continually unless I want to clean the pool. It is more costly in hardware but worth it given the cost of electricity in the area I am in.
I, myself, like to pump and filter more and chemically treat less. But I am willing to pay a price for the electricity.