My first tub (A circa 1999 nordic) did not have O3 and the water quality was poor.
my 05 Tiger River, and my 07 Caldera have a Corona dishcarge 03 unit and I have great results with the water quality. Now, I don't think it was soley the o3 unit is responsible for the inmproved water quality . This has been debated (vinny, where are you?) but i do think an 03 unit is a good investment and does work.
There have been significant improvements in 03 units in the past few years (CD units over the UV units) . The output of these units have also increased, and running them 24/7 as opposed to some tubs that only used them during set filter cycles makes a big difference. So if soemone had an older tub with an inefficent 03 unit, then i can see where someone wouldn't noticed a differnc if it stopped working, but I think with a quality unit the situation is different.
If you use your tub every day and are sanitizing as much, then it's negligable, but if the tub is used less and not santized as much, I think it makes a big difference. I can (and have) leave my tub for 10+ days without seeing a degredation in water quality.
Folks wont bat an eye and drop $120+ a yr on magic silver voo doo beads for their hot tub, but scoff at 03 units? I'd say go with the 03.
