Hi all - first, my specifics:

- IG 11k gallons with SWG, medium pebble (Stonescapes)
- Hayward cartridge filter, Polaris 380
- filter schedule is from 5pm to 11pm each day

Here are my latest test results using a Taylor K-2005:

FC: >5 (still need to get a FAS-DPD test kit)
CC: 0
TC: >5
pH: 7.4
TA: 80
CH: 330
CYA: 50
Salt: 2800
Borates: 40

The water is crystal clear until as few as one person jumps in, after which the water turns cloudy. The water always returns to crystal clear after a full filter cycle (by the next morning). I guess it's possible that the swimmers are just "dirty", but is this enough to turn the water cloudy?

Is it possible that particulate matter that the cartridge filter doesn't get is settling to the bottom after the pump turns off, then gets kicked-up after the swimmers jump in?