Our recommended hot tub water sanitation method involves three things working together:  A filter A built-in ozonator and/or ionizer Limited use of a special type of chlorine  When you purchase a tub kit from us we include a “starter kit” that has what you need to get off to a good start. The details are included in these instructions.  Here’s a summary: Follow the water treatment steps in our Water Sanitation Guidelines to keep your tub water clean and safe. As you will see, this entails regular filter cleanings/rotations (approx every two weeks), PH checking, and chlorine administration up to once per tub usage, as directed. Also if you have the ionizer you will need to monitor copper concentrations. During the first year, your cedar will release tannins into the water. Tannins offer healthful antioxidants but also react with the chlorine. Therefore during the first year, you’ll add a bit more chlorine and change the water a bit more often. After this process is complete, which typically takes about six months, you will be able to change water much less frequently — every 30–40 hot tub uses, or every four months, whichever happens first.