Post-SLAM: Failing OCLT, High Chlorine Demand, Algae behind the light?


Sep 15, 2020
Roseville, CA
Quick summary - Pool has been well balanced without issues for about a year now - I slacked on the maintenance for a few days while traveling, got a new robot for the pool so I wasnt brushing as often, and with low FC levels it comes as no surprise I spotted a very tiny algae bloom in the corner that doesn't get good water circulation. I was relying on CC levels to let me know if things started slipping. Tests have always came back at 0 - Shame on me.

Did a slam per CYA levels at 60, reasonable job at keeping it there for 2 days and brushing but with my work schedule I slacked off and went back to regular maintenance despite failing OCLT (typically 1-1.5, maybe 2 on a bad day or timing of my tests).

Chlorine demand has been crazy high the past 2 weeks but haven't had time to slam and dedicate myself to seeing it through. We're talking a gallon of 10% every day (~6+ppm) to maintain. We do however have no shade and full direct California sunlight the entire day - although failing OCLT is the nail in the coffin.

Cleaned the filters again, still consuming high chlorine. Before scheduling time to properly slam again I did some research and decided to remove the light/nitch. Pictures attached of what I found behind it - Can't tell if Algae or some dirt/silt - But hasn't been removed as far as I know since the pool was installed 5 years ago.

1) Likely this is the reason i'm failing OCLT? Algae/Not algae? Or did I just not stick with it long enough?
2) If algae - I don't own a pool vacuum and water is not at slam level (currently 10ppm FC). That being said I don't want to disturb the algae and cause a full bloom before I'm ready to slam. What is the best option here?

Current results:
FC: 10
pH 7.6
CYA 60


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Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015
Palm City/FL
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-30 Plus
The main issue is SLAM's most important letter is "M" for maintain. The more you maintain at SLAM level the shorter it will be. Check FC and adjust at least 3 times per day if at all possible. This should only be required a couple days unless you have a bad algae situation with a green pool and or debris in the pool. This isn't practical for everybody's schedule. It will still work it will just take longer. Scrubbing will help but nothing will work if you don't maintain SLAM FC level.

I hope this is helpful.

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