earlier this year I had to SLAM and I will stand up and confess. I failed the 3rd piece by not checking the OCLT. CC was 0.5 and the water was clear. I think that set me up for this need to slam again.
I came back from a week vacation and it was a bit cloudy - so I knew I had a demand since I dumped 5 GAL liquid in there before I left. Once again I am slam-ing and the water has been crystal clear since day 2.
The CC has always been borderline 0.5 (it takes the second drop to go from faintest pink to super clear). My CYA is 20 (despite adding gallons and gallons this year). I am keeping my FC levels over shock level (at least 15). pH and Ta are fine.
I am keeping on it. I am brushing and it seems pretty clean - some slight dust in the places the turno floor cleaners send dirt. Otherwise very nice!
This is day 4.
My FC last night was 23. At 7:30 this am it is 16. Each night it gets munched away.
My assumption is there has to be algae. If so, why such a huge overnight demand and I can't really see it? Is it typical for algae to be totally invisible and yet be SO very hungry for chlorine?
I suspect the answer is yes - maybe just need some validation since it is a rough exercise!!