I have a 33,000 gallon inground pool w/pebble tech finish...first time I've had a high cya level...don't know for sure why...I use liquid chlorine, shock, and tablets. I'm not sure which tablets are best: trichlor or dichlor; maybe you can help me. I realize I am going to have to drain part of the water out of the pool. Is there any other way since our state is in a terrible drought?