Just joined TFP today and am very impressed with the knowledge here. I seem to be a tri-chlor tab victim causing high CYA. I have a CYA of 150 (knowing hard to gauge > 100). I haven't added chlorine in any form for about 6 weeks - water very clear as water temp is 45 degrees . I'm having the pool drained and will be switching to liquid chlorine as much as possible in the coming summer. The question is whether I should have the ultra poz surface acid washed to get it back to the way it looked when new? Is this adviseable?