You are absolutely right. We have been in business for almost 24 years and NEVER had a problem. My repairmen had to replace a float quite awhile back, and I'm wondering if they were careless (dirty hands or such) to contaminate the tank. We are in Arizona and can be very warm. We have been battling a high TDS in our bays for months, even though our production was between 1 and 4! Everything had been checked and each time they would think "Okay this will solve it"....NOT. It wasn't until this past week that it was visibly noticeable that there was algae. They had allowed the tanks to go almost empty a couple of times in order to fill with fresh R.O. water and it would help for a short time, then the TDS would climb again. Now how to clean, disinfect, rinse, and start all over during the busiest month of the entire year! These tanks are 7' or 8' tall, 3' and 4' wide and only have about a 1' opening at the top and only one tank has a small drain. Thank you to all who respond to help out and God bless you, too...