I came across a very well written and informative article in the April 2017 Aqua Magazine entitled
"Spa Soup" Why We Dump Spa Water. The author, Robert Lowry is a recreational water expert who has been very influential in the pool and spa industry for many years. This article will help Hot Tub owners as well as manufacturers and dealers to recognize the benefits of more frequent
water changes. I certainly wish that Mr. Lowry delved deeper into the issue of Biofilm development inside the plumbing and why we should chemically flust our tubs on a regular basis as well. See the article by searching for Aqua Magazine "Spa "Soup"