February 2006
Welcome. I have an EndlessPool that has a problem. The symptom is white particles floating in the pool some of which resemble tiny pieces of facial tissue, 1mm to 5mm in diameter. When scooped up they look more green or yellow. They are slightly slimy and disintegrate when touched. They last for weeks in a jar and do not dissolve in acid, such as vinegar. I have been variously told that it is white tissue mold, white paper mold or white water mold. The pool is sparkling clear and has a Langelier Index close to neutral. This rules out the typical suggestion, which is calcium precipitation.
I have spoken with a man with a similar problem in a normal in-ground pool, so it is not just in my type of pool. The only things that our pools have in common is that the both have a retractable cover and oak trees nearby. He has not solved the problem either, but keeps it under control by heavy chlorination via an in-line chlorinator.
Since I see only a handful of links that mention such a problem, much less offer a solution, I am trolling for others who have it. If, by chance your search engine finds me, I would appreciate an email describing your experience and if you have a cure. Please send it to dick at curran dot com (where you make the obvious changes to the address) and put White Tissue Mold in the topic. As I get responses, I will post or summarize them here. Maybe together we can work out a cure.
Here is a summary of my case:
I live in Los Altos, California. The pool is partially in ground and we heat it since my wife swims every day to ease a back problem. We keep the cover closed when the pool is not in use.
The pool is small, 5000 gallons. Some have suggested that this makes it harder to control algae since it gets used every day. I would agree since I had trouble keeping the chlorine level up without daily testing until I got a floater.
I now use a floater with 3" pucks to keep the chlorine up and add a gallon of 10% liquid chlorine every couple of weeks. When I added granular chlorine manually I would occasionally have the level drop and would get algae. That may have jump-started the mold too.
The flakes are worst when we first run the propulsion system, which suggests that the mold is growing inside the channels that circulate the water.
I have a pleated paper filter and we run the filter for six hours twice a day. The filter "slimes up" quite quickly. I have taken to swapping the filter at least weekly, and soaking the alternate one in very strong chlorine to kill off anything that remains after I degrease it and hose it off.
pH is on the low side, at 7.1. I have not been successful at raising it, but given the Langelier index is neutral, I have not been concerned. If higher pH would cure the problem, I would attack it.
White tissue mold is thought to be a biofilm which is a layer of slime over the growing organism. That makes it hard to get chemicals inside to kill it off.
Update April 23, 2006
Things have improved quite a bit since I first wrote the description above. I can't say that we have solved it, but we seem to have it under control. I spoke to people at Endless Pools and they suggested "hyper-chlorination" and raising the pH. We were going on vacation for two weeks, so we decided to give it a try. I put in a new filter, added Sparkle Up to trap smaller particles, turned off the heater, and raised the chlorine level by putting 5 pucks into the floater instead of our typical 1. I also added a lot of Borax to get the pH up to about 7.5. When we returned, the filter was covered in slime so I threw it away and put in a new one. There were still some flakes in the pool, but they slowly disappeared so that now we don't see them at all.
I continue to keep the chlorine relatively high (5ppm) and the pH at 7.4 or higher. Because the pucks are acidic, it means adding Borax every week or two, but the pool has remained clear and flake free for about a month. I will add updates from time to time to let you know if this regime works for the long run.
I have receive an email from Judy who also has the problem. She had been told to empty and refill the pool. From what I have read, that is unlikely to help since the biofilm will still be on the walls of the plumbing and will happily regenerate in the new water.
Update May 25, 2006
Amazingly, there have been several people who have found this site and emailed me. Here are two links: ChrisEmail, JulieEmail. Both have much worse problems than I have had. Mine is still under control, but if I let the chlorine level drop, flakes begin to appear. I have it at 15ppm now and I am trying to get it down to 5ppm and keep it in remission. Julie has solved her problem by an impressive hunt that should become a plot line for CSI.
Here are some resources on the web that you might find useful:
PoolSolutions - A great source for pool chemistry and testing.
Sites I have found that specifically mention tissue mold or biofilms:
Update June 10, 2006
After a year we seem to have white tissue mold under control. My wife, who swims most every day, has taken charge of checking the chlorine level every time she swims and adjusting it to stay just above 5ppm. Twice during the year I had to drain the pool half way and refill it to get CYA down to a reasonable level. CYA (cyanuric acid) builds up when you use pucks and eventually gets high enough that it inhibits chlorine from doing it's job. We now only use pucks in a floater when we are on vacation and otherwise use liquid chlorine. We add 1 to 2 cups a day to keep the level at 5ppm.
And in case you wonder what our pool looks like, here is a link showing it at its best, which was right after landscaping in 2005.
