[David]

I can't help on the pump since I'm running the original 20+ year old pump. It has a brass impeler that still looks fine.

As for a $100/mo savings, like Red Beard wrote, your electric use isn't that large so there wouldn't be much savings.

In the summer I run my pump from 10am to just before 5 pm when the grid load starts to ramp up for the evening peak. In the winter I run it from noon to 4pm. Don't fall for the electric company request to run it at night, that's not when the algae grows.