Pool Tool, many thx for your thoughts. I'm pretty sure I completed the SLAM, including the extra boost of Cl to Mustard Algae levels as in
http://www.troublefreepool.com/threads/2177-Chlorine-CYA-Chart but I probably will add an extra day this time.
I will say, though, that it's hard (nearly impossible?) to scrub all surfaces. E.g., the undersides of the channel to the skimmer. And doesn't that mean that the inside of the filter canister should be scrubbed? In fact, the inside of all the piping? I'm honestly not trying to be sarcastic here; my real point is that if every surface needs to be scrubbed and that if getting the FC level high enough alone can't kill all MA, then it all seems hopeless. So while I brush accessible areas my hope is that ultimately getting FC high enough can be sufficient.
A couple other comments, though, for you or whomever else may be following this and for the web-site maintainers:
1. I interpret the "Yel/Mstrd Min" column of the above-referenced page to mean the minimum FC we should maintain to avoid MA. And if that's the case, then my original post in this thread was wrong when I said that it doesn't seem that the FC dropping to 8-8.5 should be allowing MA as it seems this chart is saying that for CYA of 60-70 we need to maintain FC at 10.5 or higher! Whereas I'd been assuming from
http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock that by keeping well above a target FC of 6 for my SWG pool I'd be safe.
2. If I'm correct that in fact I should stay at FC 10.5 or higher, then I really suggest that the page I just referenced really should have a note saying that target FC will not be sufficient to avoid MA. Or, add another column which is target FC to avoid MA.
3. A question about measuring CC: I asserted that my FAS-DPD test for CC said zero, which it did at first. But rather than immediately washing out the vial as I usually do, I stopped for lunch and upon return saw it had turned pink. So I added another drop of 0871, it went clear, and I waited 10 minutes after which it was slightly pink again. Repeating this, it appears CC might be 1.5. Then I reverted to just measuring FC to see if the same issue might be true there, and indeed after a wait the solution that had been previously clear was slightly pink.
So my question is, what's the valid way to test? Does the FAS-DPD test for FC and additional R-003 test for CC give immediate results, or does accurate measurement really require waiting a period of time. [In case anyone questions whether the initial tests weren't stirred well enough, I use a SpeedStir and the little magnetic bean spins it's heart out, so I can't believe that that bean in just 10 ml of liquid doesn't produce a nearly immediate adequate mixing.]
Thx in advance for any response.