low calcium and damage to AGP vinal liner

[waterbear]

I use chlorinating tabs in a floater and try and balance the waterwhich only needs occasional baking soda. jsamNC

And we have a very probable culprit If you are using only triclor then I suspect you had let the pH and TA crash more than once since a pool on trihcor needs nore than 'occasional baking soda'. I suspect you had extended times of very low pH which is KNOWN to destroy vinyl liners. Low calcium does not. How often had you been testing pH and TA during this time? It should have been weekly for the TA and daily for the pH.