Lots of algae, 0.5 CC

[zoffPool]

I was away for a week and now have lots of algae at the bottom of the pool. The question is with all the algae why is the Combined Chlorine level .5?

FC= 7, CYA=50, pH=7.5. TA=110

PS. The reason the FC is 7 (i think) is because I asked my wife to add chlorine tabs mid-week, And I suspect the tabs were added too late.

[PoolDoc]

It takes far higher levels of chlorine to remove algae, than to prevent it. Read the Best Guess page (linked in my blue signature bar) and adjust chlorine levels accordingly.

[zoffPool]

It takes far higher levels of chlorine to remove algae, than to prevent it. Read the Best Guess page (linked in my blue signature bar) and adjust chlorine levels accordingly.

Thanks. I guess I wasn't clear, the real question is why was the CC .5 (I'm assuming .5, because the water had the slightest hint of pink) and I had lots of algae.

[PoolDoc]

Elevated CC levels are normal ANY time you have something using up a lot of your chlorine -- algae, pee, pool party, swim lotion, yellow algae 'treatments', etc.

Eradicate the algae, and then see if you still have elevated CC levels, but don't worry about them right now.

[zoffPool]

Elevated CC levels are normal ANY time you have something using up a lot of your chlorine -- algae, pee, pool party, swim lotion, yellow algae 'treatments', etc.

Eradicate the algae, and then see if you still have elevated CC levels, but don't worry about them right now.

Do you consider .5 elevated. This is the level I've had all summer and the water was clear, why didn't the level go up when I had algae.

Thanks.

[PoolDoc]

I simply assumed that 0.5 was higher, since you asked about it.

But, if you test with the K2006 using a 10ml sample, then it's not uncommon to see some pink, which disappears with the first drop of FAS, giving a 0.5 ppm reading. My guess is, if you test with a 25 ml sample, so 1 drop of FAS = 0.2 ppm FC, instead of 0.5 ppm, you'll then see a CC level of 0.2 ppm.

If your pool is lightly used, your filter sand is clean, and you use only basic chemicals . . . you may see a 0.0 reading even with a 10 ml sample.

However, if your pool is fine otherwise, and you only see a 'first drop' CC reading . . . I don't think you need to be concerned.

[aylad]

why didn't the level go up when I had algae.

.

CC (combined chloramines) are formed when the chlorine is fighting something, like algae, in the water. They are eliminated by chlorine that finishes the job, and are also eliminated by burning off via sunlight. I've had algae blooms, bad ones that happened while my pump was out of commission, in my pool before and still had 0 CC, which is why I don't consider it a reliable sign of algae growth.