I have had AGP for 3 years now and after a bumpy start to pool ownership, this site has helped me out greatly!
This year however, I have some very weird things going on in pool - which I haven't had in past.
I have Intex 18'x52" agp w/ their swg and a sand filter, etc. (all details in sig). I use the SWG and then add liquid chlorine if it drops, etc. This year, everything had been fine. Test often w/ TF-100 kit. My CYA was a little bit low (15 ish) even though I had added enough to bring it to about 40 (per pool calc), but I made sure to stay on top of FC and keep it 3-5 range. Couple of weeks ago, GREEN/CLOUDY! Ugh - so SLAM process started. It cleared was passing OCLT, no problem. I did add small amount of clarifier from Leslies. Got CYA ramped up to ~40. I know recommended is a bit higher for SWG, but I didn't want to over-do it.
Pool was fine for 2 weeks - clear all tests good (Chlorine ~ 5 w/ OTO test).
We had people coming over on Saturday, so Friday, I added 8 oz of dichlor to boost up chlorine and CYA - should have raised by about 4.5 and 4.1 respectively. Good. Saturday afternoon CL had drifted down a bit before everybody came over and pool was clear and nice for people swimming. Saturday night - pool started looking cloudy.
I tested water and FC was at 7 CC - 0. However, I figured if it's cloudy, I might as well get on top of it. Raised chlorine to 20 (figuing that the CYA had been raised some by dichlor and should be about 45ish). Tested again Sunday noon-ish and was down to about 18, added liquid chlorine to boost to 20. Checked again last night and this AM and hadn't lost any FC.
Any idea what's going on here??? It seems that I have maintained proper FC levels to prevent algae, but it seems that something is wrong. Passed OCLT this AM, but so confused.
Using the TF-100, which is about 3 yrs old now, but from what I measure on there and add w/ pool calc, it seems to be accurate.
I am just confused. Thoughts?
Pool comes down every winter and packed away until spring.