High FC, passed OCLT, still have algae?

MainePool207

Member
Jun 1, 2016
8
Maine
EDITED: so I can add CC

FC: 17.5
CC: 0.5
CYA: 20
pH: 7.2
TA: 100
CH: 50

I think I have mustard algae, but I'm not sure why it doesn't seem to be lessening in numbers. I have two spots on the pool that have buildups in the morning and when I return home from work.

I assumed it was mustard because after SLAMming at 10FC nothing really seemed to be happening, I bumped it up to 14. The 17.5 is because I wasn't paying attention and just dumped in a gallon of 10%. I even poured in 32oz of polyquat 60 yesterday hoping for some assistance as this has been going on for several days now.

I vacuumed last night and brushed but this morning the same spots had (what I can only assume) is re-growth of the algae.

The puzzling thing to me is my FC didn't drop last night. It did the night before (by about 2 FC), but I measured 17.5 at 10pm. The sample was taken from the same spot at approximately the same depth.

Do I just need to keep SLAMming?
 
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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
11,620
Evans, Georgia
First off, can you scrape a bit off and smear it on a piece of white paper? What does it look like then?

Have you read the directions for a SLAM process? I ask because you mention a couple of varied FC levels, but neither of them is the correct level for a SLAM process when your CYA is 50ppm.

How often are you taking your FC up? The more often you can do it, say around 4 times a day test and re-dose, the faster this should go.

Are the two areas you're most concerned with in sun or shade?

Maddie :flower:
 

MainePool207

Member
Jun 1, 2016
8
Maine
First off, can you scrape a bit off and smear it on a piece of white paper? What does it look like then?
I will when I get back home this afternoon! I'm not sure how easily it will be because when I disturb the water around it (like, from brushing), it flies off in a cloud.

I have read the SLAM process and my CYA is 20 (calcium is 50).

I've only been dosing in the morning and afternoon (with the exception of this morning).

And finally, those two spots are in a shady part of the pool for the majority of the day. One is in the shallow end and the bigger patch is in the deep end.

I will edit my above post and add that I had 0.5 CC during my test this morning.
 

MainePool207

Member
Jun 1, 2016
8
Maine
Came home from work and the algae didn't "appear" as bad. The water is still very clear, it's just this stuff that keeps reappearing. The first photo is from the shallow end, and the second photo is from the deep. The black dot on the left of the second picture is a Japanese Beetle for scale :). To the right of that looks like a partial question mark is what I believe to be algae. This morning that area was more extensively covered.

20190711_185855.jpg20190711_185934.jpg

I was down from 17.5 to 13 FC so I put in more and my FC is back to 15.5 (the 42oz from pool math put me up over 15).

Would pollen survive through the SLAM and dissipate like a mist when brushed?
 
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MainePool207

Member
Jun 1, 2016
8
Maine
My CYA is 20, Mustard SLAM is 14. I posted why it was 15.5. The Pool Math page told me to put in 42oz. I did. And as I last posted, my end test showed 15.5.

I didn't want 15.5.... I dosed for 14......

I've SLAMed with 10FC with no luck, hence my question of mustard algae and why I'm SLAMming at 14.