Need some help with yellow/mustard algae

Clarifying my point, my SWG could produce enough FC to maintain 5-6ppm at 75% output in the heart of texas summer sun. So 100% output should theoretically build up FC in the pool under those same circumstances, and surely now with less sunlight.

I understand swg needs to be off for a while & pump running for 30+ min before any FC testing, and after sunset and before sunrise.

Thanks
 
Clarifying my point, my SWG could produce enough FC to maintain 5-6ppm at 75% output in the heart of texas summer sun.
Probably...? Will have to test and see.
So 100% output should theoretically build up FC in the pool under those same circumstances, and surely now with less sunlight.
Ha, Ha. Yes, theoretically, it is possible, but the cell output is not necessarily linear IRL, and may or may not meet specs from the manufacturer.

I did a test with mine a couple summers ago. My SWCG is supposed to produce 13FC running 24hrs at 100%. I wanted to see if I could get pool to SLAM level. During the test, in the summer, I could not get it to raise the pool above 13-14FC.

I did it again last week, by accident I left it on 55% for a couple days. When I tested it was 18FC.
 
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no, Im stating fact based on my settings and FC measurement :).
It just doesn't work that way IRL. It is a hypothesis, that probably is correct, but until you test IRL, you don't know. We are not in summer now. You have no idea how many pools we've seen where assumptions didn't meet reality, for one reason or another.
 
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There's a point where you stop creating dead-algae cells and you begin waiting for the filter to pick them all up. But one of the 3 exit points for SLAM is "crystal clear" water, so you wouldn't be passing if you still see dead algae. So - continue to SLAM, but as you near the end, you'll find that FC holds immensely longer than when you first started to SLAM.
 
my FC is dropping so I know I still have active organics. But could at least some of my dusty debris be sand? Not sure where it would come from, but the bowls are collecting some (that circuit has its own pump and no filter).
 

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You've been at this for a while, and when that happens I always go back to basic TFP concepts:
- Algae cannot survive in properly chlorinated water. That we know. If algae is alive, then the SLAM Process works if the CYA and FC are tested accurately and the SLAM maintained.
- Sometimes a hidden area for algae is a pool owner's nemesis. Now that you've exposed the drain covers, there shouldn't be anything left. I believe you also checked behind the weir door correct? No pool cover being used, etc? No handrails in the water? Anything touching the water that hasn't been inspected/cleaned?
- It's still a bit hot in TX, so if your CYA is on the low end you'll loose FC each day regardless. That's normal. It's the Overnight Chlorine Loss Test that will be your true measurement of success. If you fail that, with accurate FC testing, then there must be algae somewhere.
 
I dont know what a weir door is. Light removed and niche cleaned.
No pool cover. No handrails. Nothing touching the water. All toys & floats removed and sanitized.

OCLT coming up in 30min, so we’ll see where things are.

RE the sand, where would it come from? Could the pebble finish “release” sand?
 
the sand, where would it come from? Could the pebble finish “release” sand?
I doubt it's from the pool's surface unless you had a really bad install, it was very old, or the chemistry was really, really bad (corrosive) for a long time. The only other way "sand" would get in the pool is if there was something locally that could've blown in or been swept in during a heavy rain. There's no mistaking sand for its gritty texture, so more than likely it's just dirty/dust that has settled. Dead algae would be very light color (white or light grey) and be very fluffy.
 
Assuming they come off?
They can, but some can be tricky, so don't do anything that might break it. If you can't figure out how to remove it, just remove the skimmer lid as if you were going to clean the basket. Then look inside. You should be able to see and reach the inside of the weir door. You should be able to inspect the foam backing to tell if it is moldy or anything else.
 
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OCLT result; FC held overnight. Zero loss.
Fantastic! The dusty stuff may be just that - dust. Based on everything you have been doing for quite a while, no FC loss, crystal clear water, I think you're fine. Of course back to your original thread title about MA. If you feel MA is still a concern, now is the time to take it up to the MA level for 24 hrs. Otherwise, I'd let it fall and just continue to clean the pool like normal.
 

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