Holy Cow! I can't believe it: someone else who has the EXACT same experience as me!
I have just read your entire thread with utter fascination, as I have been fighting the same battle as you. I had originally posted last fall about my mustard algae issues. The short story is, I had a brand new fiberglass pool installed last summer (2017). The pool installer was horrible, put the pool in the ground (with water from a truck), then never returned to finish the job for 2 months. Meanwhile, the water sat untreated. New to pool ownership, I had no idea what that was doing to my pool water. When they finally turned the pool over to me in late August, it was a swamp. I quickly started reading the internet to learn how to clean it up, and came across this site. I followed the SLAM procedure and the water cleared, all except for some brownish looking stuff that I assumed was left-over dirt from construction. To keep my story from becoming too long, suffice it to say that I eventually realized it was not dirt but mustard algae. So our brand new pool was never able to be used, and I, like you, spent 2 solid months following to the letter every instruction on how to kill the mustard algae, with no success. (I only had that long because of a very mild fall.) I finally gave up and closed the pool in November. When it was opened in May, the same battle started all over again. I too have a SWG that I have not even used because I'm trying to get rid of the algae first. I too have spent all my free time brushing and vacuuming the pool, have maintained FC at up to 150% of CYA for weeks at a time (and never letting it drop below 60% of CYA), and whenever I think you may be winning the fight, I get up in the morning and there is one tiny spot of mustard algae still there, which then grows. My husband also got mad at me for spending so much time on the pool, said I should just listen to the people at the pool store, but of course I have been reluctant to use anything not recommended on TFP. (We are now getting divorced, btw.) I have read anything and everything on the subject, both here and elsewhere. I feel I have become an expert on pool chemistry. Of all the reading, my favorite posts are the ones by ChemGeek, (what ever happened to him?) and I have pored over everything I can find by him on the subject. I love good science. And yet I can't beat the zombie algae, as I have come to call it.
Like you, I have started to look for anything else I can possibly try, as doing the same thing over and over again and expecting a different result is the definition of insanity. When I had posted here last fall, I got the standard replies: beginning lessons on the SLAM process, reiterating the rules, etc., which, like you, I appreciated. But after all I've been through, I know what is supposed to be working, and it's not. I also had the same thought as you regarding this being a particularly resistant strain of mustard algae. I am a physician, and I know that in medicine we are constantly seeing bacteria that mutate and become resistant to antibiotics. Whereas 50 years ago, penicillin killed just about any strain of bacteria, there are now plenty of bugs that aren't touched by it. That's what organisms in nature do - mutate to find ways to protect themselves. It is certainly very reasonable to think that this particular strain of mustard algae has mutated to make itself incredibly resistant to chlorine. And those numbers for the mustard algae SLAM by ChemGeek were all theoretical. There was never any large, controlled study done to prove that those numbers were absolute truth. From reading his stuff, I think he would be the first to say that. He never claimed that there couldn't be exceptions to the rules. Those numbers were what seemed to work for most people. And they were formulated several years ago. Many new mutations could have happened since then. The point is that I have come to the same place as you -- the TFP method is great and works in the overwhelming majority of situations, but there are some very rare instances (like ours) that require at least some modification to the standard approach. I had also come to the conclusion that there must be a biofilm protecting it, because I passed the OCLT over and over again, had clear water, and yet the mustard algae was always still there. I figured if it wasn't causing the chlorine level to drop, the chlorine must not be getting to it. Truth be told, as of a few weeks ago, I had pretty much given up and assumed there was nothing I was ever going to be able to do to kill this algae. But today I thought, maybe I need to try to check for phosphates and try to treat them, as I had never gone that route. I signed on here just to read up again on phosphates and see if anyone else had posted about mustard algae, and, lo and behold, I came across your thread. (I was always thinking, there must be SOMEONE else out there dealing with this. But all the posts from people who had MA seemed to revolve around using a sodium bromide product and dealing with problems from that. I never saw anyone who actually had dealt with mustard algae come on and say they defeated it using the mustard algae SLAM technique and everything was now great.)
So you have no idea how excited I am to read your story and find someone with likely the same strain of mustard algae that I have, (I'm in northeast Ohio, not far from the Pennsylvania border), who has been fighting it religiously for months on end like I have, and has had the same lack of results. But it sounds like you finally won, and I'm so encouraged by that!!! I did not know there was a product that could attack the biofilm. I am going to look into it right away. Thank you, thank you!!
