Actually, one of the very first pages I posted on PoolSolutions, probably in 1997, pointed out that raising hardness or adding calcium was NOT needed in liner pools. At that time, all the pool books and all the pool stores indicated that it was needed.

It's somewhat gratifying to me, that the 'mainstream' pool business is now drifting toward acknowledgement of that fact. Unfortunately, your dealer is apparently one of those who wants to hang on to his profits, no matter what the facts are.