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It is a good addition to the spa but it certainly isn't the be all and end all. Will you recoup the cost of it with chemical savings? No, but it does help and if you know what it's like to feel the frustration that some people have in caring for their water I say it's well worth the $60-$90 per year in cost (IMO).
I agree. I add about a tsp dichlor to my 485 gallon spa after use but its in between uses that I feel the value is. I can go days in between uses with a N2 cartridge without the water going bad. You can certainly get by for less money without it, but it makes a nice companion to dichlor. Some do, but I would not use it with only MPS in place of chlorine.
Hey Bill,I know you're a chemical engineer.What would be the factors that makes N2 work in your tub and not mine? Water with PH OK, calcium around 160 PPM and a person using dichlor should react the same - Should it not?The only difference is my ozonator is on for about 12 hours a day.Any thoughts?