Agreed, they are expensive, but can be found for a good price on fleabay. Acid addition for me is about 1 qt a week during summer for a 20K/gal pool. There is additional power requirements to make the Cl, although I haven't taken the time to calculate how much that really is. The biggest savings is that I spend about 20 minutes a month fiddling with the chemistry of the pool.
Michael
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