Can't quite eliminate CC

[donovan.lambright]

I have an Intex pool, around 4,000 gallons. The CYA level is about 75 ppm and I've been keeping the FC level around 10 ppm, as per the Best Guess Guide to Swimming Pool Chlorine chart. Recently, after a couple of days of heavy rain, I slacked off a bit and let the FC drop to about 8 ppm. The water was clear and looked fine but, just to be safe, I raised it up to 12 ppm and let it sit. There is now a bit of yellowish residue at the bottom of the pool, which I assume is algae.

The water is still clear so I was planning to just vacuum up the stuff on the bottom and be done with it. But yesterday, I found that my CC level was .5 ppm. So I raised the FC to 20 ppm. This morning, I found the FC is still 20 ppm but I also still have a CC of .5 ppm.

I'm thinking that the elevated CC means that I'm still fighting algae, even though the water looks clear. On the Best Guess chart, 20 ppm of FC is shown as shock level. I'm a little worried that it sat all night at 20 but I'm still showing some CC. Should I should raise the FC even more or let it be for a day?

It's raining again today so there's not much sun to drive off the Chlorine. Not sure it matters here but I use dichlor pellets to maintain my FC and bleach to temporarily raise it.

Thanks!

[CarlD]

Hi.
A CC of .5 means .5 or less...nothing to worry about. Depending, the yellow stuff COULD be pollen. I got tons of yellow pollen for several years, so thick it would coat my skimmer sock like butter-yellow spackle paste!

Dichlor will continue to raise your CYA level, 9ppm for every 10ppm of Free Chlorine it adds. You'd be better off switching to bleach/Liquid Chlorine or Cal-Hypo.

[Watermom]

Brush your pool while the chlorine is high.