Hi All,
I currently have a 18x36 IG vinyl pool with a 1HP Sta-Rite Duraglas pump and a 300lb sand filter (likely changing to DE though). The plumbing of the pool is 1.5", I have 2 returns to the pool, 2 stair "spa" jets and a return to the spa that allows me to heat the spa or if I turn a valve allows spillover into the pool.

I have found lately that it takes FORVEVER and a day for the pump to prime. It's especially noticeable while vacuuming but once it's primed it seems to run fine. I don't have any leaks. I was thinking the pump is worn out (it's only 4 years old though) and was considering replacing it with a Hayward Northstar. I just don't know how big to buy it. I don't want a huge monster but I also want enough flow and a decent electricity bill. Any thoughts or tips?

Thanks!
J.