Hello and again thanks for the fine advice; I have saved so much by following this Forum methods rather than the "recommendations" from the Pool Store Supplies.
This just started happening, my CYA levels are high, 110.
Here are the measurements from today on a 18,000 gallon, plaster inground pool:
Cl at or less than 1
I have used "Pool Time" powder which lists Sodium Dichlor as 99% of the content, and had good results, crystaline water. Yet in the last few weeks, my CYA readings are high and Chlorine levels very low.
I am in Southern California, where water is not cheap, and although not a Scrooge I will drain, about 2 feet of water and replace from the faucet, rebalance and see what happens. AND stay away from the dichlor.