I'm pretty sure from previous posts that Vermonter has already tested ozone and N2 to the best his instruments can, at least with as much time he can justify on curiousity about his hobby. I think he also has done some in-tub tests of various routines. I believe that was the basis for his famous (on internet spa forums) dichlor routine. If I recall correctly, he found that dichlor was effective at controlling bacteria, silver was measurable and slowed bacteria down but didn't control it, and ozone in the tub was not measurable and had little effect on bacteria growth (in the tub).
As for people's different experiences, water make-up is only one of many variables. For example, use by one adult may result in a different bacteria load and amount of oxidizable material than a parent and two teenagers. Somebody who says they use their tub 3X week, may in fact only rarely get in more than twice -- 33% less use. One person may call a rounded teaspoon 1 tsp, while another may level theirs. As you know, the same chlorine dose at 7.2 pH is much more effective than one in a 7.8 pH tub. The amount of CC, TDS and CYA in the water may affect the way the chemicals work, as may application order/timing. What one person calls good water may be another's cloudy/foamy, etc. That is what makes anecdotal information hard to make sense of. :-/ I'll take Vermonter's info over that.
First, I agree 100% that Vermonter's method is a great way to treat the tub. When I went into a D1 store and they were trying to sell me on the Vision system and doesn't need dichlor unless you use the tub more than 3x a week, I mentioned about dosing after use and the dealer laughed at me and that was the most ridiculous thing he ever heard ... of course that was right after him telling me that I don't need dichlor ...
Second, I believe Vermonter did say he did measure some silver ions but it was at the lowest that his instruments can go and he didn't measure ozone. My understanding about any test or measurements is that info is skewed at the top and bottom of the instrument testing range and you want to be at around 75% of the highest range your testing for (ie: 75% of say 250). He also has said he runs ozone on his tub, this is in years past post and maybe he has changed it - I didn't catch that part.
Third, when I used N2 I did expect the tub to last longer and not get cloudy but it did in 2 days with me using ozone 8 hours a day as recommended by my dealer (another person who questions ozone, she actually talked me out of the mixing chamber). The interesting thing is she recommends only the N2 cartridge and the enhanced shock once a week, I can't see how and her other customers have great water with it. My primary sanitizer was dichlor at 3 PPM per person and I believe I was using enhanced shock at the time on a weekly basis. I will say I was trying to run my tub similarly like my pool and it didn't behave too well. Part of my problem could have been a new tub and our usage pattern was different (just cleaned suits and the like) and maybe I didn't quite get the whole hot tub water routine vs pool water routine. My last water change (April to July) was the first time my water actually lasted that long and I replaced it because it was old, I was only getting 1 1 /2 months out of the water before that, so maybe I finally got it (I'll see since I'm my 1 1/2 moth mark now).
I do question any system that is expensive by nature (ozone, N2, Vision, Frog, ...) with respect to dichlor and to a lesser extent bromine (only because I have never used it). If I buy a 5 lb jug for $30 and put enough dichlor to properly sanitize my tub - why do I need anything else. I believe that these helper systems work to some extent but am I really only going to use 0.5 PPM dichlor vs 1.5 PPM - for me probably not. I did read Vermonter say that there is a cumulative effect of using more than 1 sanitizer but is it really going to make a difference in my tub using the amounts of dichlor that I use - that's the question. I have to say based on my previous experience with N2 that if my boys stuck their heads in my tub and N2 was in there they still probably would have gotten ear infections.
But that was then and this is now. I may experiment with N2 again just to see if it will make a difference. As of ozone, I do have it running 24/7 now and I will attempt to see if it does make a difference for me.
It's funny you mention people's water quality, my oldest won't go into water that doesn't measure up to his standards based on what our pool and tub water looks like - you're correct there too, not everybody's standards are the same!
