12/11/2012
Water is precious, so if you have a hot tub the question is: When should I drain my hot tub?
First, while spa companies recommend quarterly drains, there's some misinformation in that answer.
Barring no real problems with green water or some other nasty water issue, the only parameter to drain a hot tub is Total Dissolved Solids (TDS). End of story.
Think of your hot tub like a giant tea pot. When you use the hot tub and distill the water the TDS raises incrementally. When TDS reaches 1500 ppm that's when it's time to drain the hot tub.
Why? High TDS lessens the effect of your chemicals. And when minerals fall out of solution your spa’s innards will look like the inside of your teapot. It’s okay for the teapot, but not for motors, pumps, heaters and plumbing. Think expensive repair bills.
High TDS symptoms: You can’t keep your chemicals in solution, no matter how much you add, your spa has no water quality, bad smells, etc.
You can purchase a TDS meter usually for under $25.