The few times I had mustard algae, many years ago, it was only on the pool wall, shallow end side wall, the one that didn't get direct afternoon sun, and a bright yellow. Mine was kind of like a thinly veiled area about 4' X 6' and always in the same spot. The water was very clear so that probably made the color more prominent. I got on it so fast, indiscriminately dumping "tons" of granular chlorine in pool, pretty close to area probably reaching shock levels many times greater than needed, immediately started brushing, and ran the pump and cleaner 24/7 for at least a week. I actually have run pump and cleaners almost that much anyway for 24 years. And I've always hyper-managed the pool when I am not out of town (dog/house/plant sitters or house keepers were "made" to hyper-manage the pool when I wasn't here - that's about the only thing they had to do that sometimes drove them to tears worrying so much that they would make a mistake - shoot, all those years of hyper-management included many good intentions, but never the less mistakes, made by me ----- until discovering TFP last year) so it never got a good hold. By the next morning, after HYPER Shocking, there were no visible signs of it. I really didn't get to observe it in its dieing or dead state as I usually treated in evening and probably killed all living things that got too close to the pool that ended up in the filter before I saw the pool in the morning. I'm glad I had at least enough sense to keep the dogs out of the pool for a few days.
I don't know if mustard algae is as much a problem in cooler climates as it is around these parts but it is a huge battle for many pool owners/care takers, around this area. I don't know any pool owners other than me and the people I converted to ionization, (I sincerely regret doing that now), when they were using ionization with adequate metal levels, that don't have several battles with mustard algae every summer, year after year after year. In summer our local Leslie's can't keep the shelves stocked fast enough with Yellow stuff.
Another thing that contributes to mustard algae is areas that have inadequate water movement, or "dead zones" or where cleaners don't reach if circulation is inadequate or so I've read.
I never had mustard algae or any other algae in my pool, for about 18 years after switching to ionization (or whenever Nature 2 came onto the market), with one exception. Before ionization I used bromine feeder and before that chlorine feeder, both probably putting way too much sanitizer in the pool. I switched from chlorine to bromine soon after we moved here because the chlorine was bleaching out the show dog coats; even the fawn colored Mastiffs. They lost the varying highlight colors. The Bromine, was actually no more costly than chlorine. (BTW... Now that I'm using BBB method, there is, of course, no chlorine smell AND the black Labradoodles show no sign of their black coats being afftect by the chlorine at all. They were in the pool for many hours a day, last summer and fall.) The upfront cost for Bromine was more but it lasted longer. I switched to ionization because DH couldn't handle the chemicals. This was before people recognized the importance of chemical balance and cya/chlorine relationship. (Many people "in the industry" still don't know about cya/chlorine relationship.) I did have mustard algae a few times way back before ionization but cleared it up pretty quickly using tons of granular chlorine and brushing. And this was prior to getting my first Polaris, which I've always used many hours a day. One summer I tried the Nature 2 express, which fed less metal into the pool than my big commercial canister and pool did get a touch of mustard algae. That was the one time I used Yellow Out, or what ever if is called, and it took more time to clear it up than good old chlorine I used back in the old days and cost a whole lot more. It's been so long ago.
BUT, BIG BUT, how sanitary was my pool then and, yes, they, three different systems, did cause eventual metal staining. I fell for the "low chlorine" and shocking every once in a while mentality. There were a few exceptions to having no-algae pool. Several winters, for various reasons I couldn't be here to manage the massive amount of stuff going into pool, in fall and winter, and had to shut pool down, uncovered, leading to green algae only, which grows most months of the year, due to our usually mild winters. At least it was green (bottom brown and mucky but stayed there as long as it wasn't disturbed) until water started warming at end of winter. Then it went pretty quickly to greenish tan, then greenish brown, then greenish dark brown, and then black if I didn't get it cleaned out or drained out in time. I don't think mustard algae could have lived in those conditions.
All those years, up to today, everybody I knew/know with pools, who weren't using ionization constantly fought/fight mustard algae in summer and fall. I'm sorry to say I was responsible for converting quite a few people to ionization.
But I didn't know any better.
Since switching to BBB I haven't had a speck of any kind of algae, even this winter into spring without a pool pump and filter running for two months. Thanks to TFP I used submersible pumps to keep the water moving (I actually knew about that before), chems totally in balance, and cleaned, somewhat filterd, and circulated with a very old used Aquabot running many hours a day.
If all pool owners/care takers could or would subscribe to the practices prescribed on TFP, Pool School, and The Pool Calculator, yellow algae would be a pool "plague" of the past. It will still hang around and it is so opportunistic. It will rear its ugly "heads" if guard is let down; "guard" being well managed pool. It loves any pool that is even slightly mismanaged for a short period of time.
I forgot the question.
gg=alice
