How do they explain the effectiveness of chlorine in saltwater chlorine generator pools that typically have 3000 ppm salt in them (in the U.S.; in Australia it's 5000 ppm salt), let alone ocean salt pools with 35,000 ppm? What they are saying is total baloney. Also, Trichlor adds salt to the pool as well since ALL chlorine does that since the chlorine when used up becomes chloride (salt). However, while chlorinating liquid or bleach add twice as much sodium chloride salt as Trichlor, the Trichlor adds CYA which is far worse to build up than salt.
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.
The CYA from Trichlor is not added separately. Trichlor is a chemical that is a combination of chlorine attached to CYA. In the water, the chlorine is released from the Trichlor and the CYA remains ("
trichloroisocyanuric acid" is three chlorine bound to
cyanuric acid where you can see they are the same except that the chlorine "Cl" are replaced by hydrogen "H" which is what happens when the Trichlor gets into the water). The chlorine gets used up, but the CYA does not so it builds up. If you used "pure" Trichlor at a rate of 2 ppm FC per day, you'd increase the CYA level in the pool by 36 ppm per month.
Was this just some college kid who was temporarily hired during the summer to handle peak demand or was this a permanent employee or even the owner of the store? If the latter, you may remind them that fraud is illegal.