Troubling FC and CC numbers -- crystal clear pool

cooltouch

Well-known member
Jun 4, 2018
112
Houston, Texas
Folks, I've been testing my pool's FC and CC numbers every morning and adding chlorinating liquid as required. I've been shooting for a 7ppm balance and typically with my pool I'm having to add anywhere from 40 oz to 64 oz of bleach a day. The actual numbers I'm seeing are usually around 3.5 to 4.5 ppm for FCs and 0.5 or less for CCs. But this morning, I ran the test and I got 2ppm FCs and 1.5ppm CCs. Yet my pool remains crystal clear. Oh, and I tested the water twice and got the same results.

We've had some rainy weather recently, so there's been a lot of leaves and twigs I've had to fish out of the pool, and when it wasn't raining, we've had plenty of bright sun. But with earlier days, the numbers were within what I've come to see as acceptable parameters.

So anyway, I'm wondering if my pool is trying to work up an algal bloom even though there's no visible trace of algae? Should I think about doing a quick SLAM even though there's no visible algae or cloudiness? I'm really curious what tomorrow's tests will show.
 

JamesW

TFP Expert
Mar 2, 2011
17,462
For minor CCs, I would go to a fc/cya of about 25% and do an OCLT.

Typically, the CCs will go away with elevated fc and sunlight.

What is the CYA?
 

cooltouch

Well-known member
Jun 4, 2018
112
Houston, Texas
CYA is 40.

Maddie, just to make sure I'm following your recommendations, namely "take it up to 10 tonight (test to confirm)" I'm assuming here that if I add the additional bleach to bring it up to 10 ppm tonight that I should also run the pump to make sure the bleach has been well circulated before I test tonight.

Oh, and I should mention that the test this morning was back in the normal range. FCs were 5 ppm and CCs were 0.5 ppm. This is with a target of 7 ppm FCs. So, maybe yesterday was just some sort of fluke perhaps? Considering that these were real numbers, though, I'm still curious as to why the sudden dip. I dumped a lot of bleach in the pool yesterday, though, so maybe that was enough to snap it out of whatever was going on.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
12,433
Evans, Georgia
The reason I suggest you take it to 10ppm is that you're hovering about 7, so it makes it a bit easier to take it up over your norm (with SWG off!) and you should be able to notice a drop in the AM easier. Make sure to test late at nght, and again early in the AM before the sun hits the pool so you know any loss isn't from the sun.

Maddie :flower:
 

cooltouch

Well-known member
Jun 4, 2018
112
Houston, Texas
Mine is not a salt water pool.

Maddie, I know all that stuff. I was merely asking if you run the pump to circulate the chlorine. Seems to me you'd have to for at least a few hours.

Those numbers from a few days ago must have just been a strange little anomaly. Today's numbers were back within the range I'm used to seeing. FCs were 3.5 ppm, CCs were 0.5 ppm. I'm used to seeing between 3.5 and 5.5 ppm for the FCs and the CCs are usually never higher than 0.5 ppm.
 
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duraleigh

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Apr 1, 2007
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Sebring, Florida
Those numbers from a few days ago must have just been a strange little anomaly.
I completely agree. No need top panic over a slight variation in one day of testing.

If it were my pool, I would continue to do exactly as you have been. I would not perform an OCLT nor change anything you are doing. If it ain't broke.....