First up thanks to everyone, love this site, have learned so much, I switched last year from trichlor tabs and dichlor shock to BBB and just liquid bleach, had a great season!
So I opened my pool this Sat, when I closed my pool last year CYA was about 35-40, I was surprised when it was 0 at opening (loads of leaves had gotten through the security cover somehow and must have caused the "swamp" effect and eaten all the CYA).
Tested water (TF-100) before adding anything -
Air temp - about 75F
TA - about 90-100
PH - about 7.2
CYA - 0
FC - 0
I happened to have a bunch of unused di-chlor shock packs (aqua chem brand) from before i switched to using BBB, and knowing that it adds Chlorine and CYA I though i could use that to increase CYA. I added a pack and a half (one pack says 12,000 and i have an 18,000 gal pool) on Sat morning and then tested CYA on Sun night and it was still not registering, though FC was about 1 and CC was about 1, so I added another pack and a half and then tested Mon morning and finally the CYA test liquid was looking a bit cloudy but still not registering on the CYA tube (which has a min of 20, so I estimated it must be about 5 or so) FC was 1, CC was 4. Water had cleared up significantly and was looking much better.
So I plan to keep adding the dichlor shock to bring the CYA up to about 30-35 or so and then stop and use BBB as usual. Any problems in using dichlor to increase CYA like this?
thanks in advance!