Been slamming for 18 days so far

[ltfdrebbin]

Hello. I've had to SLAM our pool in the past and it worked.
Now I'm not sure what is going wrong.
We are on day 18.
Our CYA started at 60, so I've been getting the FC up to 24 and then letting it get as low as 14. We are adding liquid chlorine 4-6 times daily and have added more than 200 gallons!
We still are getting a few algae spots daily.
Our overnight OCLT has always been .5 or less.
The water is much more clear, but still has a ways to go.

What are we doing wrong to make this take so long and not be as effective?
Thanks

 

[Kaylee34]

I had a super long slam early this summer. I feel your pain!
Are you brushing well at least once a day? Have you checked everywhere for hidden algae pockets and scrubbed those areas?
Most important, you have to MAINTAIN your FC at SLAM levels until you pass all 3 criteria. If you're letting it drift back down to 14, you're letting algae keep a foothold.

 

[bertschb]

Most important, you have to MAINTAIN your FC at SLAM levels until you pass all 3 criteria. If you're letting it drift back down to 14, you're letting algae keep a foothold.

Bingo!

 

[mknauss]

Just to clarify, the SLAM level FC is the level one should target when testing and adding chlorine. Not over that. The more often you can test and add, the better. As long as the FC is above the minimum for the CYA level, algae is being killed, albeit very slowly.

 

[Fpppool]

When I had a case of stubborn mustard algae I drained like 10 inches to drop the CYA to 30 and SLAM it following mustard algae SLAM levels. Took almost two weeks, 80 gallons of chlorine 10% and daily brushing. Also, started with a clean filter.

Chlorine/CYA Chart

EDIT: You will find a simplified and standardized version of this chart at Pool School, Chlorine / CYA Chart. Chlorine/CYA Chart by Chemgeek FC = Free Chlorine in parts-per-million (ppm) CYA = Cyanuric Acid in parts-per-million (ppm) CYA ........... Min FC3 ..... Target FC ...... Yel/Mstrd...

www.troublefreepool.com

 

[IceShadow]

As mentioned, check for hidden spots. Lights, weir doors, ladders, we even had someone who had a bunch of algae in the crevices around his in-wall ladder and had to scrub that out with an old toothbrush to really get rid of the algae there.

Is the pool cloudy? If so, it could be a filtration issue. Are you cleaning your filter cartridges when PSI goes to 25% over clean value?

 

[Momma4]

I went ahead and took our ladder out during our slam and treated it separately with straight bleach when it was out on the pool deck. I took the pool light completely out and had to scrub inside of the casing to really get everything. Good luck!