Quote Originally Posted by 94ukgrad View Post
I disolved about 2 lbs of CYA in a sock hanging in the pool from end of water hose. This was done 7 days ago. Also, I have used 3 trichlor tab in the last 4 days by putting in the skimmer basket. They really dissolve fast in there.
Next time pour the CYA into the skimmer very slowly, run the filter 24.7 for about 2-3 days, don't clean your filter for a week and there you have it. In most cases you should see the CYA in a few days. No need to hang it in a sock unless you are trying to clear a green pool and backwashing a lot. Hanging the sock in the pool is a very slow way to add CYA IMHO.

Now in your first post you said you used 3 lbs and here you said 2 lbs. In either case in a 21K gal pool you are talking about only a 10 or 15 ppm increase and that is too low to measure!

Add an additional 4 lbs and then test for it. You should be right about where you need to be. without knowing the weight of the trichor tablets you used it's impossible to say now much CYA they added but since most tabs are around 6-8 oz I am guessing they added about another 6 or 7 ppm in total. Still below testing threshold.