Replace old inefficient pump with new more efficient pump

[Watermom]

A sand filter will have to be backwashed several times each season, and will dump 200 - 300 gallons of dirty -- maybe greenish -- water SOMEWHERE, each time.

HUH?? When I backwash my sand filter, I would guess I lose no more than 50 gallons (high estimate) of water each time. I usually backwash for a minute or maybe a minute and a half.

[PoolDoc]

In-ground pool with a 1HP pump => probably 40GPM or more on backwash.

5 minute backwash (mfg standard) at 45 GPM = 225 gallons

Watermom, your pool has a smaller pump (1HP AG pumps < 1HP IG pumps) and smaller filter, BUT I'd bet if you look at flow, you STILL are dumping more than 50 gallons.

[Watermom]

I have a full-rated 1/2 hp inground pump on my AG pool with a 200 lb. sand filter. I don't think I have ever backwashed for 5 minutes. 1 to 1-1/2 minutes is more like it.