I have a 15k gallon in ground plaster SWG pool. My TA was 40 about 2 weeks ago. Since then I've added 16 pounds of Calcium Chloride to bring my CH up from 140 to 290. I've added 40 ounces (need to add more) CYA to bring it up from 35, shooting for 70, I'm at 45 now. My pH was at 7.6, but has climbed a little to 7.8 now (since it has been 3 weeks, which is normal). My question though is what could have brought my TA up from 40 to 60 now in 2 weeks? The only other thing I've added to my pool since then is Bioguard Backup 2 which has been very effective in killing the water bugs I was having a bit of a problem with. Could the Bioguard Backup I've been adding cause it to go up? The active ingredient is Alkyl dimethylbenzylammonium chloride.....could this have caused the TA rise? I'm not complaining because I actually WANTED to increase my TA a bit, but I'm just curious now what caused it so I'll know.