I would leave it at 12 ppm for one more day, just to be on the safe side, but if you went from 7 pm last night until 6 am this morning with no chlorine loss, I'd say you're in pretty good shape. If you can keep it at 12 all day, and go all night tonight without losing any chlorine, then I'd say let it drift back down to the 3-5 range tomorrow and go swimming!! Might want to squeeze the sock a little to encourage the last of the CYA to dissolve, then tomorrow morning test your CYA, and we can adjust your baseline chlorine from there. Once you mix the pool water with the CYA reagent, let the bottle sit on the counter for 3 or 4 minutes. Then shake it again and run your test for CYA. If you're not sure, you can always pour the mixture from the tube with the dot in it back into your original container and do the test again. It's a very subjective test, but we need to know what yours is to determine whether to add more CYA or how low to let the chlorine go.

You've done a great job--keep at it, just a little longer--I'm getting the feeling that crystal clear pool is right around the corner!!

Janet