The other half wanted a house with a pool when we bought three years ago. Came with a pretty big one, vinyl liner 20' x 50' x avg 4.5 deep. Hayward 1.5hp "super pump" (yeah....) 230v. Hayward 300 pound (S224T) sand filter, lightly rusted gas heater ( which I cut out of the system early on - reduce head ) mechanical timer, freeze control. Two skimmers, one bottom drain, four returns. The five lines at the "pad" going down thu concrete are 2" ( with the attendant gyrations of reducers and runs of 1.5" here and there) but I suspect as they head toward the pool they get reduced.
So Its bugged me for three years, how many gpm, pump is only about 15" above the top of the water and about 10' horizontally. The fugly plumping at the "pad" has a slightly unnerving rhythmic rhythm to it. Couple of weeks ago got a blue white pitot style flow meter from a local pool supply, "how come you want to know that?", cause I do... They only had one for 2.5" pvc and mine was 1.5" coming out of the filter with the minimum straight run for the meter to read right. Yes they are pipe size specific, changed that run to 2" and the unbelievable 240gpm dropped to about 150 but still a mismatch. Pool store ordered proper one for 2" line. Now it measured between 90 and 100 gpm depending on if it is just back flushed. May not still be accurate but probably not to far off.
The super pump quit while I was out of town... a few days ago. Good, didn't like it anyway ( 8 to 9 amps measured at the circuit breaker panel) Started net surfing to get ideas, found this site and now have the official chemistry set and have been grateful for the info available on various topics. I now have confirmed I have been wasting money on electricity, stressing the system with too much flow (sand filter is rated for only 62 gpm) the filter is undersized, and the "pool boy" at 250$ per month, he int worth it (CYA level is about 100), the pool store suggests I raise the CH level a bit (currently 130) to help protect the liner, etc...
I'm going to try a pentair vs pump and have been thinking for a couple of years that a cartridge filter (pool boy dont like em, said he'd charge extra to maintain it) would drop the head a bunch compared to the amazing number of course reversals water has to do to get thru a "multiport" valve ---how ever... thanks to the available data here, I see the head loss on a multiport valve verses a cartridge is probably insignificant at 30gpm (my target flow after renovations) compared to 60gpm or 90 fpm!
So my question, if anyone is still reading this....How much should I worry about the half sized sand filter? (adding a polaris 280), an identical one year old hayward S224T is available locally (owner going to fill in the pool with dirt) and I am wondering about getting it and adding it in parallel to the existing one. Thoughts anyone? (I am changing the sand in the existing one)