eric61 Posted May 4, 2021 Report Share Posted May 4, 2021 Hi All! Just found this site and feel that the hot tub world is beginning to make sense. I have a 390 Gallon HT with an ozonator and had been using the Nature 2 + MPS, which seemed to be working fine. However, it appears my wife is sensitive to the MPS (started getting a poison ivy type rash) which made me look into other methods and came across this site (I was already getting skeptical of the costs anyway). My question is basically: should I dump the water and start over (I just refilled less than a month ago) or can I convert it over? Here are my latest tests: FC 1ppm, TCl 1.8pp, cya 76, Ph 7.5, TA 50. I assume the MPS just gets used up so I started adding bleach since the cya was high. Have not added borax. Water seems clear and good. I am in northern CA so feel bad about dumping the water. Additionally, is it OK to leave the nature 2 cartridge in since it is only a month old or does it actually cause harm? Thanks in advance... -eric Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted May 5, 2021 Report Share Posted May 5, 2021 Nature2 is compatible with and, in my opinion, works better with chlorine. I use ozone, nature2, and chlorine in my tub. I don't even own mps. 1 Quote Link to comment Share on other sites More sharing options...
eric61 Posted May 5, 2021 Author Report Share Posted May 5, 2021 Thanks. What level of FC do you target? Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted May 5, 2021 Report Share Posted May 5, 2021 I don't. I have 24/7 ozone injection so, since ozone eats chlorine, it's a lesson in futility. I hit it after use and leave the cover open for 30 minutes or so. By the next day when I open the cover the chlorine has sanitized the water and the resulting cc and most of the excess fc will be gone from the water. Quote Link to comment Share on other sites More sharing options...
eric61 Posted May 5, 2021 Author Report Share Posted May 5, 2021 Makes Sense. One more question: how much chlorine do you hit it with after use? Quote Link to comment Share on other sites More sharing options...
waterbear Posted May 5, 2021 Report Share Posted May 5, 2021 bring it up to a minimum of 2 ppm FC if you are leaving the N2 in the tub. Personally, I would maintain the FC at 3 to 6 ppm with a CYA of 30 ppm If your CYA is higher then you need to run the FC higher to maintain the same sanitier activity. The N2 is a silver nitrate cartridge. Silver has very slow kill times, is ineffective against viruses, and is better suited to drinking water sanitation where the water is in a contact chamber with no introduction of contaminants (bathers), which would requires a FAST acting residual sanitizer. SIlver/MPS with HOT water (as found in a hot tub) ARE an effective sanitizer but, as you noted, some people are sensitive to MPS. Once you switch to chlorine with silver you are relying on the chlorine to handle the bather load and the silver works when the tub is not in use to supplement the chlorine. Fun facts: EVERY person that enters the tub involuntarily urinates about 5─10 mL in the water and involuntarily releases about 10─25 mg of fecal matter (Courtesy of Taylor Technologies). They also sweat and sweat and urine are almost chemically identical. The water to bather ratio in a tub (most are under 500 gallons) is extremely small when compared to a pool (average size of most residential pool is 15,000 to 20,000 gallons) or even a swim spa (normally in the range of 1500, to 2500 gallons) so a fact acting residual sanitizer is a must! Quote Link to comment Share on other sites More sharing options...
eric61 Posted May 5, 2021 Author Report Share Posted May 5, 2021 Thank you, this makes sense. I think I will dump half the water to get the cya into the 30s then rebalance, etc. Quote Link to comment Share on other sites More sharing options...
eric61 Posted May 7, 2021 Author Report Share Posted May 7, 2021 On 5/4/2021 at 7:00 PM, RDspaguy said: I don't. I have 24/7 ozone injection so, since ozone eats chlorine, it's a lesson in futility. I hit it after use and leave the cover open for 30 minutes or so. By the next day when I open the cover the chlorine has sanitized the water and the resulting cc and most of the excess fc will be gone from the water. Another question: with your set-up, what do you do when you go away (say for more than a couple days)? Quote Link to comment Share on other sites More sharing options...
waterbear Posted May 7, 2021 Report Share Posted May 7, 2021 There are a few ways to deal with this situation. My preferred method for more than a day or two is: 1. maintain a 30-50 ppm borate level in the tub 2. shock with chlorine before you leave and then turn off the tub if possible 3. shock again with chlorine when you return and restart the tub. if you can't turn it off the tub circulate at the lowest speed and turn of ozone if you can. Quote Link to comment Share on other sites More sharing options...
eric61 Posted May 7, 2021 Author Report Share Posted May 7, 2021 Makes sense. What ppm of shock do you go for before turning it off? Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted May 8, 2021 Report Share Posted May 8, 2021 Go away? Like, leave the house? For more than one day? Is that possible? People DO that? Oh... they must not have kids. 🤪 Quote Link to comment Share on other sites More sharing options...
eric61 Posted May 8, 2021 Author Report Share Posted May 8, 2021 Lol. Believe it or not, they do eventually grow up (or at least get old enough to send away 😂) Quote Link to comment Share on other sites More sharing options...
eric61 Posted May 9, 2021 Author Report Share Posted May 9, 2021 On 5/7/2021 at 8:30 AM, waterbear said: There are a few ways to deal with this situation. My preferred method for more than a day or two is: 1. maintain a 30-50 ppm borate level in the tub 2. shock with chlorine before you leave and then turn off the tub if possible 3. shock again with chlorine when you return and restart the tub. if you can't turn it off the tub circulate at the lowest speed and turn of ozone if you can. @waterbear: another question (sorry to pester, just still trying to wrap my head around all the details). If I have an ozonator (running 8 hrs/day) and a N2 cartridge and, say, shock to 10-12ppm then cover and leave for a few days, the chlorine will eventually go to 0 but will the ozonator and N2 maintain sanitation given no use? or at least for awhile? Quote Link to comment Share on other sites More sharing options...
waterbear Posted May 9, 2021 Report Share Posted May 9, 2021 IF there is no use of the tub and nothing is growing in the pipes than it will should be sanitized but I would still shock it before use. Just because water looks clear and has no off odor does not mean that it's sanitized. I also do not like to leave a tub unattended for a few days or longer and running. You never know when there might be a leak, mechanical, or electrical problem that needs quick attention. Quote Link to comment Share on other sites More sharing options...
dashmer Posted May 20, 2021 Report Share Posted May 20, 2021 @waterbear, what PPM of FC do you recommend shocking to? I am hoping to be away for 8 or 9 days this summer and may not have anyone to dose the tub while I am away. Thanks Quote Link to comment Share on other sites More sharing options...
waterbear Posted May 20, 2021 Report Share Posted May 20, 2021 If your CYA is 30 to 50 ppm then shock to 15 ppm for vacation. Sbock again when you return and wait for FC to drop below 10 ppm before entering tub. If CYA is below 30 ppm shock to 12 ppm and once again when you return to 12 ppm. Quote Link to comment Share on other sites More sharing options...
dashmer Posted May 21, 2021 Report Share Posted May 21, 2021 Thanks waterbear. Great info. Quote Link to comment Share on other sites More sharing options...
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