It's plain and simple to understand if you take a look at the pictures in on this website and in this post. Most hot tub and spa owners change the water 3-4 times a year. They clean out the shell and refill it with water and add chemicals. What's missing in this picture? Well for one, bio-film is always present on the pipe walls and in the jets and this gunk needs to be flushed out before you change the water. I just cleaned out my lawyer's hot tub ... owed him some money and my hourly … [Read more...]