First time OCLT test, what insight does this provide

[ramsfan]

Hello, long story, but a week ago, my water was perfectly clear and balanced. I may have accidentally let my FC get to zero or near zero for a very short time (no more than a day, and likely less than that). I had read that SLAM should be considered if FC ever dropped to zero. I did some more research and came across OCLT.

Here are the steps I took last night and am curious what my results indicate. I could also do another OCLT test again tonight, as I know there can be variability in testing, and I did not get up before sunlight!

At 9pm after sun down, and after SWG had been shut off for an hour and filter still running.
pH 7.3
CYA 60
FC 6 (measured via DPD)

I ran filter overnight

At 6am this morning (unfortunately the sun had risen (maybe an hour or less, but our pool faces East and the morning sun can get intense)

pH 7.3
CYA 60
FC 4 (measured via DPD).

My water looks clear, but not as clear as it did this past weekend, but that could be due to large amount of pollen here, the surface has a lot of it.

My question...... Does the drop of 2 in FC indicate a problem that would necessitate a SLAM? Or, does a drop of 2 in FC indicate a "mild" issue that can be addressed with a more conservative approach?

I am open to advice, retesting, etc...

 

[woodyp]

I'd advise a SLAM. Pollen isn't going to consume 2ppm in an hour of early daylight. May you be blessed with a very short SLAM..........you ain't exactly cleaning a swamp!

 

[rmturner54]

I'd advise a SLAM. Pollen isn't going to consume 2ppm in an hour of early daylight. May you be blessed with a very short SLAM..........you ain't exactly cleaning a swamp!

I agree . You might also once you pass the oclt, raise your cya to 70 to 80. Amd follow the fc chart for cua levels