I could make a bunch of jokes and I'm tempted but the real lesson is that you have to do your own testing.

They don't know how to run the tests any better than you do. They dip fancier strips and then plug the RESULTS into the computer that gives them a list of things to try to sell you. They make it sound like they have a fancy machine with special electronics that "taste" the water and tell you what's in it, but they don't.

SOME use drop testing--they should be a little more reliable, but use strips.

It's true in the pool biz, and it's true in the tropical fish biz, where the water tests are similar. One local store, a GREAT store, NJ Pets, got taken over by Petco. All the brands we liked of pet products were replaced by the same stuff available anywhere--at premium prices. And, when my son kept fish, we brought samples there and they were ORDERED by headquarters to stop using drop testing and only use strip testing. The staff were very apologetic but they didn't want to get fired....and we never went back to Petco for anything.