So... A new pool season, yet another question about MA.
Background: I have been managing a minor case of MA for the past 2 years. It never gets out of control, but I have yet to beat it despite attempts at MA shock, frequent brushing, etc.
This season appears to be no different. While keeping the pool at proper FC/CYA ratio, MA will *slowly* grow. My standard protocol has been to brush when I see the first hint of yellow and that keeps it at bay for several weeks. (My guess is that if I brushed every week I would never see it.)
Question: Shouldn't brushed off MA lower FC levels in a similar way to garden variety green algae?
I ask because yesterday I noticed a "heavier" growth than normal after a few days of minor neglect. So after brushing the entire pool, which made the water slightly cloudy, I surmised that the FC had dropped to close to zero and added 12ppm FC to head off any growth of the brushed off algae. Today I tested the water fully expecting an FC value considerably less than 12, but instead measured 11.5!
Obviously this means that FC was not as low as I had guessed to begin with, but I'm still confused about the role of mustard algae in regard to FC. First of all, I don't really understand why it always remains in check instead of taking over the way that green algae does. And secondly, I totally don't understand how I can never really measure the impact on FC even after brushing away what seems like a significant amount of it. Just doesn't seem to be behaving as I would expect algae to behave.
Anyone care to venture an idea(s)?