ABQ_Pool said:
I think I'll hold off on the OCLT for now - the pool has had some chlorine swings (I've always had 2-3 pucks in the skimmers at all times, pump running 24x7 and I've supplemented with Clorox), but I don't think it's been low enough for long enough to have an algae issue (I hope). I haven't earned my Pool School degree yet, but wouldn't my CC be higher if I truly had an algae issue? It was less than 0.5 yesterday and 0 today (I'm still trying to dial in my SWG and the FC was 8.5 this AM

)
Wanna hear my algae salt story? (no algae salt exists, that's a joke)
My pool is always maintained daily with chlorine. I rarely get even .5ppm CC.
CYA at 40. So I dose the pool to 7.5ppm with my son. We're actually having a lesson so we test, and then add precisely 1 cup 2oz for each ppm chlorine we want to add. I tipped the pool with a little over half a cup (.5ppm) for being such a good pool that day.
Later that evening H and I added salt. And brushed. It dissolved nicely.
The next day I realize one of our cats is missing and spend the day looking for her. About noon that day I look into the pool and it seems a little... "dull" smelling. Later that day I think I catch a tint of green as the last of the sun ducks behind the house and off the pool. But I disregard that for the moment because we're all hot and tired from posting flyers for the cat, a kid wants to swim.
So it continues to smell just a bit off. It rarely smells anything other than fresh, so this is a bigger red flag to me than the hint of green I thought I saw. An hour after the kid swam I found the time to test. Guess what? A big whopping 0 FC. Nothing. Nada.
I've never seen 0 FC before, not since we switched to BBB last season. I was shocked to say the least. I'd just dosed the pool to above the high target the night before like I always do. I never fall below minimum, and certainly not 0 by six pm.
So I blamed the salt. And posted here about it but after discussing it, it probably was not the salt or if it was, there was something in/on the bag that was not brand new (stored in our garage).
There was one incident about a week before that I'd found the pool to be at 1.5ppm. I had been gone for a day at my cousin's wedding, drank enough to make me tired and forgot to dose the pool at 3am when we got home that night. It was a sunny day, a for sure dose day but since it was like the FIRST sunny hot day we'd had all summer I blew it off. Sun makes a huge difference in chlorine loss. I can skip dosing on cloudy days easily.
Anyway, that is the only below minimum incident I can report of all summer. It was a week before the algae bloom. And I think it just coincided with the salt addition rather than any result of the salt.
Moral of the algae salt story is... algae will git ya, and it can git ya fast.
Good news is, because I was able to test, then shock, then maintain, and then do the OCLT the next night. Kids were swimming the day after shocking once the FC was under 10ppm.
See? Algae salt! lol