Wanted to check in and see if anyone else had something similar occur with their TWW. I use the espresso profile and combine with water from my RO. I mix in a glass carboy and refill my reservoir as needed. A little bit ago, we went on a week vacation and returned to find my water reservoir with a faint red colored ting and a gross film along the inside walls of the water reservoir. This had never happened before when I was using plain RO water or bottled water. Also, I only get the film on the reservoir, no issues in the carboy. Since that time, I will do frequent soap scrubs, followed by PBW, followed by Star-San sanitizer to the reservoir, its components, and the carboy as well. Despite all of that, I continue to find that I will still get this film albeit to a lesser extent. Any ideas from you all as to potential cause and cure?
I did reach out to TWW, and they suggested the possibility of the kitchen RO system being contaminated. The only issue I have with that theory is that nothing else seems affected. Not the carboy, not the water bottles we use for daily consumption, etc. Should I try a different product and see if the issue goes away? Again, any help would be appreciated.

Depending on your RO setup you maybe removing all the chlorine from the water so it is more prone to bacterial growth. A contaminated RO system would definitely explain the consistency in the re-appearance of the same bacterial film. But then this should happen if you let your bottles of drinking water sit for a while as well. If not then it is probably just an initial load of bacteria on the reservoir due to your cleaning being unable to completely disinfecting it

If the water temperature in the reservoir of the Profitec 700 is warmer than the carboy, this might promote biofilm slime growth.

Bacms wrote:Depending on your RO setup you maybe removing all the chlorine from the water so it is more prone to bacterial growth. A contaminated RO system would definitely explain the consistency in the re-appearance of the same bacterial film. But then this should happen if you let your bottles of drinking water sit for a while as well. If not then it is probably just an initial load of bacteria on the reservoir due to your cleaning being unable to completely disinfecting it

I am going to have the guy who services my RO system come out and check it just to be sure. As you pointed out, I haven't noticed build up in the carboy so maybe it is just the reservoir. I may try to completely disassemble it, including the valve in the bottom as soak in white vinegar prior to star san next time.

yakster wrote:If the water temperature in the reservoir of the Profitec 700 is warmer than the carboy, this might promote biofilm slime growth.

It absolutely is. My machine is turned on sometimes half of the day, and the reservoir water does get warm. Not hot, but certainly warmer than room temp.

I've had my HX for about 1.5 years and I noticed slime on the walls of the water container only once. I've also read this happens from time to time in water reservoirs and so the recommendation was to clean it every few weeks. I usually replace the water in my steam boiler every 3 weeks and at that time I try to time it so the reservoir will be empty.. I then clean it with a small amount of bleach/water and then rinse thoroughly and let dry.. They refill. I haven't had the issue again. I haven't noticed any slime in subsequent cleanings.

I also use RO (from store) & TWW.. don't think it is related to that at all.. slime is a bio thing. (unless you somehow have some bacteria in your RO source, but generally they remove everything)

Every tank machine I've had regardless of water being used would develop a bit of scum over time, so I got in the habit of washing with dish detergent, then rinsing well every 1.5-2 weeks and it's not an issue. The heat/cool cycling over and over has to cause this along with possible contaminants in the air, etc.

I have to clean my water cooler periodically that I use with RO in plastic carboys because of this issue, even with the UV sterilizer parts. I think it's more likely to happen with dechlorinated water and may happen more frequently with warm or hot water.

At least one "pink" bacteria feeds on soaps or detergents I believe. So rinsing after cleansing is important. I have a tendency to do the bleach /vinegar routine myself.

Good to know. What do you personally do with bleach/vinegar solutions?