The Chlorine vs CYA relationship, although long known, is not widely recognized by the NSPF or the APSP or other pool orgainizations. This I belive is due to lobbying by the chemical makers. It will take the national swimming pool and spa organizations to change the game, so the chemical folks lobby hard against it.
If the NSPF or the APSP did recognize and recommend maintaining your pool the way we do, the chemical makers would loose TONS of sales.
I know i harp on Pool Stores pretty hard, but I really do belive that all those folks know about pool care, for the most part, is from the product sales literature. I dont think the folks on the pool store do it on purpose. They just dont know any better.
Although, there are some that do, I have no doubt.