I looked at your pool cooler:

I need to talk to them. I would have expected a cooler like that to be useless in Louisiana.

As to what I think of your pool company's chemical advice - I thought I'd made that clear. They are chemical idiots: if they knew even a little about pool chemistry, they'd never claim that the scale was calcium chloride!

Also, I'd bet on your problem being purely a manufacturing defect. If you think there's the slightest chance of legal action, I'd save EVERY thing you can from them. If you can find the "calcium chloride scale" claim, in writing save, date, and get a witness signature on the copy. Take that into court, and with ANY swimming pool witness, it's a slam-dunk to show that they don't have a clue.

Ideal ranges -- for them -- are going to be anything they claim, or hope, will reduce the appearance of their defects, and have nothing to do with actual pool chemistry. If you can do so without destroying your pool, follow their guidelines, regardless of how stupid they are, and document doing so.

And if going to court is an option, I'd talk to an attorney sooner rather than later. Of course, the company may be near bankruptcy, in which case you've just got to do the best you can. I'd certainly want to find out what I could about the company's finances. If you can sue first, you may be able to get a settlement BEFORE they go belly up!