We have a spa that only gets occasional use (once every few weeks right now), and I'm wondering how best to keep it balanced. Right now I'm using the Nature2+MPS system. The instructions talk about shocking before each use and once a week, but if the tub doesn't get used during the week, is it OK to let the MPS level drop to zero in between the once-a-week shock?
My other concern is temperature. As I understand it, the spa temperature needs to be kept around 100 for Nature2+MPS to be effective. Since we're not using the spa very often, it would make more sense (and save $$$) to be able to keep the temperature lower most of the time, but does this mean I can't use Nature2? If I lower the temp and switch to chlorine (or the dichlor+bleach method), what adjustments would I need to make to those regimens given the low usage? I read somewhere that you can't let the chlorine level drop to zero- would I need to shock daily even if the spa isn't getting used?