I have a 50 lb tub of Poolife 3" 3-in-1 Cleaning Tablets that I've never opened. (Came with the pool) My CYA is at about 25 so I need to increase it but have no stabilizer on hand. I was trying to figure out how many will get me to about a 40 CYA when I noticed copper in the ingredients. It's a very small % but I'm concerned. Can I use just enough to add about 15 CYA? And if so, how many will that be?