We got a small Costco hot tub last December, and have been running it with chlorine. I test the water before getting in, and add some chlorine as needed, waiting 15 minutes and retesting before entering. After using for 15 or 20 minutes, I add 1 tsp of chlorine granules per person. If we use it again the next day, there's usually enough chlorine remaining that I don't have to add any before getting in. However, if it's been a couple days, I usually have to add a heaping tsp.
More and more frequently, it only gets used once or twice a week. This means I end up having to put as much as 3 tsp of chlorine in before using, which is, as I recall, about as much as I use when putting in new water. This tells me that I need to keep up on it better, and add check chlorine levels every couple of days even if it won't be used. However, I don't always remember to do that. So I'm a little worried about stuff growing in the water between uses.
I saw a Nature2 mineral sanitizer cartridge on Amazon, and I ordered it, hoping that if I put it in, it would keep things safe if the chlorine level drops between uses. However, in reading the instructions, it appears that it's not going to do what I want. For one thing, I'd need to switch the roles of MPS and chlorine. But in reading the fine print, chlorine can actually be substituted for MPS. So now I'm confused. Can I use this cartridge for my intended purpose, or should I send it back?
