Okay - just openend pool on 5/22 as the weather has turned from rainy and 50's to 80's seemingly overnight...
I noticed this last summer but could not seem to overcome it despite shocking, brushing, vacuuming, etc. There is a tannish-colored dirt or algae or sand on the bottom of the pool. when I brush it it forms a cloud. I have tried vacuuming and things look good until a couple hours later and it is back. I've really noticed this increasing ever since I switched from cartridge to a sand filter (don't know if it is related). We do live on a gravel road and it is quite dusty but never noticed this when using the cartridge filter.
This year it seems some of the spots don't come up when i brush (like they are stuck on the liner). I also have two greenish stains in the corner of the pool and partially on the side.
It is 3 days since we opened it and the water looks fairly clear but really not sparkling and the bottom obviously looks dirty.
Here are my test results...
5/22 - opened and put in 2 gal. pool chlorine (10%)
FC - 13.5
CC - 0
CYA - 60
PH - 7.8
TA - 180
CH - 220
Added 1 gal chlorine
FC - 14.5
CC - 0
CYA - 35 (? accuracy)
PH - 8.2
Added 16 0z. PHDown (Sodium Bisulfate)
FC - 13
CC - 0
PH - 8
CYA - 45 - 50
It has been really sunny so I don't think the loss of choline has been that great. but I just added another gallon chlorine when I saw the greenish stain/spots on the bootm/wall. Should I add more PH Down?
Any suggestions on the how to get the dirt off the bottom and keep it off?