Hi Matt
I was tired when I responded and I realized it might help if I clarify what I did in an attempt to prevent the yo yo effect (even though the dose was small for my size of pool).
Btw...the reason I keep using the Aquafinesse is due to its effect on biofilm. And...it seems to have helped kill any spiders (especially wolf) that make it into my pool. It used to be such a problem that kids didn't want to swim in it (prior to mustard algae issue).
Added info: What I use in the pool is salt, liquid stabilizer, muriatic acid, baking soda (rarely), the Aquafinesse tabs, 10% liquid chlorine for an occasional shock Tx and when treating algae, 88% NaBr (already explained), and if CH is below 200 I use Cal Hypo 73% when I want to shock.
Before starting to use the NaBr, I did make sure my FC level was at Pool Math shock level and that the pH started off low (7.2) and TA was stable at 90 (works best for my pool).
Instead of adding 20 oz NaBr and 4 gallons of 10% chlorine, I added 6 oz of NaBr and 2 gallons of the chlorine.
Then, the next day I add the same amount of 10% chlorine to keep the cycle going without dipping into the pre-treatment FC amount.
The 3rd through 4th day I tested FC like I would have for a SLAM. I decided to look at any drop in FC to be due to the effects of the NaBr and made up my mind to add liquid chlorine to bring the level back up to the pre-determined shock level.
On the 3rd day, there was only a few light grayish white patches reappearing (and not as frequent) and sparse gray dust clouds when brushing the slant.
On the 4th day, there were no dust clouds and there was only 2 small spots that appeared (only once) in the corner and their appearance was like I had never seen before (the sediment appearance had changed to what looked like a whitish fluff?!). I focused heavily on that area that whole day.
Day 5 had no dust clouds and no signs of the algae. So... that night, around 8 PM I tested the water and made sure my FC was at or near shock level and shut off the SWG.
Day 6 around 7 AM, I tested the FC level and there was no FC loss and CC continued to be zero (which is what it was even before I started the process), I then turned the SWG back on.
Side note - my salt avg reading on the SWG increased on day 2 ( I don't rely on it but it has been consistent so I thought I would monitor it throughout the next few weeks).
From Day 6 onward, I chose to brush every other day, check FC in AM and PM, and not add any more NaBr. I wanted to see how long it stuck around.
What has me stumped is......My overnight test from day 5 onward showed no FC loss, but the salt level remained constant (at day 2 value), and there were no signs of algae. Then around day 18, that small amount of algae reappeared in the deep slant corner and the salt level dropped back down to pre-treatment level. Does that mean the NaBr was no longer around at day 5 or day 18 (which would be more realistic). Per one of ChemGeek's posts from the past, the NaBr does eventually deteriorate due the sun and no longer impacts the available chlorine.
I appreciate the conversation concerning this and hope everyone realizes the reason I put this in this forum was to generate discussion concerning the topic without swaying others who may have just begun having issues with this algae and may have success with TFP method
Louanne