Choosing a pool pump

We may need to replace our old 2 hp pump. We have an 11,000 gallon gunnite pool, with a raised spa/waterfall. Our filter is a Purex Triton FNSP 60.

What size pump should we get? I'd really like to lower our electricity bill. Regarding the spa, we haven't used it in years, and don't necessarily need a larger pump to accommodate it.

I'm now wondering if we actually have a 2 speed pump? When the spa is turned on, the pump/pressure seems to increase a bit to get the jets going.

See if you can find a manufacturers label on both the pump and motor. The mods would be better able to help you with this.