OCLT good…but algae still in pool

[300winmag]

in ground pool. Full tx sun.
Pebble finish
SWG (currently off)
Spa overflow, 3 fountains and 2 vertical bubble columns. All running during the SLAM
CYA is 50
Ph of 7.2 at start of SLAM
Maintaining SLAM FC of 20ppm.

I lost 1.0 ppm of FC overnight, but I still have yellow mustard algae on the walls and floor. So, the SLAM will continue.

I’ve been at this for several days now and I’m shocked how much Crud I still stir up when brushing.
My question is, at some point will the SLAM rid the pool of the stuff I’m stirring up? Or maybe the filter is supposed to catch it?

Thanks

 

[PoolStored]

My question is, at some point will the SLAM rid the pool of the stuff I’m stirring up? Or maybe the filter is supposed to catch it?

Yes. How often are you brushing? Did you scrub behind the light? Under the drain covers?

Do me a solid and retest your CYA using these instructions:

CYA - Cyanuric Acid Test

Cyanuric acid (CYA) is the chemical name for the product commonly called “pool water stabilizer” … Read more…

www.troublefreepool.com

 

[300winmag]

Brushing at least 4 times per day
Scrubbed the light….not the drains!

Retested cya w this method and got 50. It obscured at 40, + 10. So 50.
Before i was just looking when the dot disappeared, which was at 50. So maybe I lost 10ppm of cya during this?

 

[PoolStored]

Before i was just looking when the dot disappeared, which was at 50. So maybe I lost 10ppm of cya during this?

Testing variance. Ignore it. CYA is 50. Strong indirect light is the key to this test. Get those covers off and scrub...PUMP OFF (AT THE BREAKER).
Good job.

 

[300winmag]

Im about to lose daylight…

If i only lost 1ppm last night, ok to shut her down overnight, fire it up in the AM and get to the drains when I can?

Or best to leave it all running overnight at 20ppm FC?

 

[PoolStored]

Or best to leave it all running overnight at 20ppm FC?

Leave it running 24/7 until SLAM is complete.

 

[300winmag]

Had momma handle the kids and I jumped in.

One of six drains had some crud under it. But both light boxes were LOADED with it. Cleaned everything and reinstalled.

Pool back on. Brushed it again.

 

[YippeeSkippy]

Don't bother to do an OCTL until after the pool is "Gin clear".

 

[300winmag]

Still brushing up the dusty crud.


As a general question, if 20ppm FC is good for my CYA level, what makes higher FC not good? Does it just lose potency / effectiveness above a certain level? Does it interact with the CYA making it effective only to a certain ratio?

 

[PoolStored]

Most FC gets bound to CYA (95-99% dependent on pH, temp etc.) The Active/unbound FC is HOCl. As HOCl is used, CYA releases more, but the % of FC that is HOCl doesn't change.
The % of FC that is HOCl is dependent on the CYA level (pH etc).
SLAM level FC maintains enough active chlorine (HOCl) to kill Algae.
Raising FC won't do any more than SLAM level FC.
It is about MAINTAINING FC that kills the algae, not MORE.