To all forum readers: RDspaguy has performed his "purge test" on an 18 year old hot tub that was, IMHO, was neglected by the previous owner(s). Based on the fact that it was left to the elements and froze, creating a gigantic mess to repair, it was a hot tub that was probably not maintained to the traditional standards we all strive to achieve. Obviously, I am biased as I am the manufacturer of the Ahh-Some products, but there was no question that RD's test would validate what many hot tub owners, dealers and manufacturers already know. Our product does work and work's fast. We perform a chemical plumbing colonoscopy that is extremely effective. Not to beat a dead horse here but it should be noted that test results by America's leading biofilm engineering university, Montana State in Bozeman, has written that the Ahh-Some is over 5,000 times more effective in bio-remediation than one of the leading brands I shall not name here. These test results are online if you investigate. Actually, we have much test data on numerous other competitive products as well. Thank You RD for your efforts. Your "in the field" trial and inspection was performed without bias or for profit motives. You are a well-respected forum contributor whose postings are based on your many years of "on the job" experience. Thank you.