Cloudy water. Surprisingly huge FC loss with OCLT??

MostlyCanuck

Bronze Supporter
Mar 19, 2021
186
Toronto, Ontario, Canada
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
noticed water was v cloudy yesterday. FC about zero. I had the SWGC on very low output given colder weather we just went through but last few days heat and sun shot up, I didn’t adjust it and clearly it lost ground so wasn’t producing enough chlorine.

Tried running it 100% for a few hrs but wasn’t catching up fast enough. So turned it off and took water to slam level. This morning water is still v cloudy (no visible algae or dirt) OCLT outcome was FC loss of 8ppm.

That 8ppm loss seems huge to me given aside from cloudiness water looks fine (not green, no algae that I can see). Is it possible my reagents are bad?! I’ll keep this going but wanted some thoughts from you folks…
 
Hey MC !!! Algae is microscopic and it grows exponentially. By the time you can see it, you have a runaway train. Your testing will tell you what your eyes may or may not see.

Glad you caught it before it was a swamp. :)
Full speed ahead with the SLAM. Test/add as often ad you can, preferably every 2 - 3 hours. Brush and vac 1-2 times a day. Clean the filter at 25% PSI increase. Every inch gets scrubbed, stairs/ladders drained, etc.

You got this.
 
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thx for the cheer! could use it... so depressing to see the water turn into a cloud :(

My CC is confusing though - I always thought it was the main indicator of algae in water... but in my case water is visibly cloudy - and I hear you when you all say it's definitely algae - but my CCs are consistently zero since starting the SLAM which you would think means there is none?!

Is cloudiness necessarily algae? could it not be dissolved solids / dust / other organic matter that just didn't make it through the filter yet? My backyard right now is under constant attack from a ton of trees shedding pollen and other flying stuff... and likely will be for the next couple weeks at least. could it not be that?
 
My CC is confusing though - I always thought it was the main indicator of algae in water... but in my case water is visibly cloudy - and I hear you when you all say it's definitely algae - but my CCs are consistently zero since starting the SLAM which you would think means there is none?!

Is cloudiness necessarily algae? could it not be dissolved solids / dust / other organic matter that just didn't make it through the filter yet? My backyard right now is under constant attack from a ton of trees shedding pollen and other flying stuff... and likely will be for the next couple weeks at least. could it not be that?
CC is a funny thing, it's not always there.

Could it be "dissolved solids / dust / other organic matter" - sure, part of it. But the inability of the SWCG to keep up with the FC loss is the telling part.

If it were my pool I'd turn off the SWCG and SLAM with liquid. No need wearing out the SWCG - it can't keep up and the little chlorine it's adding is insignificant
 
Pollen clouded me every spring on a heavily treed yard.

It can also mask a growing algae bloom with you assuming it's debris.

I may also be dead algae that was killed prior and already outgassed the CCs so they are not apparent now.

Or some of all of the above.

The Overnight Chlorine Loss Test is needed to remove the daily FC loss (sun / UV) from the equation. If you lose FC overnight, it's organics/algae in the water.
 
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CC is a funny thing, it's not always there.

Could it be "dissolved solids / dust / other organic matter" - sure, part of it. But the inability of the SWCG to keep up with the FC loss is the telling part.

If it were my pool I'd turn off the SWCG and SLAM with liquid. No need wearing out the SWCG - it can't keep up and the little chlorine it's adding is insignificant
yeah, that's what I'm doing right now. sounds like the right approach.. was just wondering if it's a seasonal thing that's bound to happen every time there's a hot spring with high temps and tons of flying pollen....

thx for the advice all
 
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Even if you pass the OCLT you keep the FC at SLAM until the water is clear. (And .5 CCs or less). You don't want to get behind the 8 ball if it was algae. The FC will hold pretry well and not need that much attention, it's just good insurance.
 
The presence of cc’s above 0.5ppm is indicative of organics but the absence of cc’s does not mean the absence of organics- this is why it is only 1 of the 3 prongs of the method & to ensure everything is eradicated you must satisfy ALL 3 -
*Cc’s of 0.5 or less
*Pass Overnight Chlorine Loss Test
*Crystal clear water
 
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Even if you pass the OCLT you keep the FC at SLAM until the water is clear. (And .5 CCs or less). You don't want to get behind the 8 ball if it was algae. The FC will hold pretry well and not need that much attention, it's just good insurance.
Thank you. Water was back to crystal clear yesterday aft and this morning I validated no overnight loss and CC of 0.5 (which for some reason I’ve always had for two yrs at virtually every reading) - so it looks like now I’m back to normal… after two days and a whopping 28lt (and $50) worth of liquid chlorine. Feeling good about outcome and thx all for advice. It was a v expensive way of removing cloudiness from the water though and hopefully won’t happen again for a long while..
 

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The presence of cc’s above 0.5ppm is indicative of organics but the absence of cc’s does not mean the absence of organics- this is why it is only 1 of the 3 prongs of the method & to ensure everything is eradicated you must satisfy ALL 3 -
*Cc’s of 0.5 or less
*Pass Overnight Chlorine Loss Test
*Crystal clear water
Re the indicator you mention… at that low level of 0.5 is the difference from zero statistically insignificant? I ask before I’ve registered .5 CC at virtually every reading, ever…. Which makes me think detection at that level is inaccurate and there’s no meaningful difference between 0 and 0.5 - is that correct?
 
CC of 0.5 (which for some reason I’ve always had for two yes at virtually every reading)
That's a normal amount from the healthy process at any given moment and also the variance of the kit. Then add human error if that drop wasn't perfectly perfect, and yeah. All good. (y)
It was a v expensive way of removing cloudiness from the water though and hopefully won’t happen again for a long while..
Never land near minimum and you should be free and 'clear' indefinitely. The term is way too Ok-ish sounding for me. I want to rename it 'swampville' and see if folks respect it more like they should. @Jimrahbe calls it a cliff that you don't want to get too close too, for good reason.
Which makes me think detection at that level is inaccurate and there’s no statistical difference between 0 and 0.5 - is that correct?
Correct. More than that means something is brewing. Now. Common sense comes into play at times as well. You'd expect to have more after a big swim day, but if nothing was happening recently, you'd want 0 or .5.
 
Never land near minimum and you should be free and 'clear' indefinitel
What caused my issue was me not paying attention to swift, dramatic weather changes impacting chlorine consumption. SWG was set very low for early spring with cloudy days and colder weather which we had the past 2-3 weeks since opening and producing enough (in fact, slightly above range). Then 3-4 days ago temps literally nearly doubled to peak summer levels… I didn’t adjust SWG output and it couldn’t produce enough. My fault but brutal… the tech I have is so expensive that the automation should really have some integration with weather monitoring to keep SWG output in sync with air temps. If there’s any clever engineers reading this, pls build that now!!!
 
the tech I have is so expensive that the automation should really have some integration with weather monitoring to keep SWG output in sync with air temps. If there’s any clever engineers reading this, pls build that now!!!
I'm too lazy to care. Or bother fiddling. I run hot and I'm good for whatever happens, from extra sunshine/temps to big storms to impromptu swims with friends. I'm pre-covered.

Some folks like the challenge to see how low they can go. Others are particularly frugal. I salute them both but it's not for me.
 
I'm too lazy to care. Or bother fiddling. I run hot and I'm good for whatever happens, from extra sunshine/temps to big storms to impromptu swims with friends. I'm pre-covered.

Some folks like the challenge to see how low they can go. Others are particularly frugal. I salute them both but it's not for me.
what do you mean you "run hot"? I wasn't referring to the water heater temperature but the salt water output.. you can set the salt cell to produce chlorine from 0% to 100% - where very low output produces appropriate amount of chlorine for colder/clouder days while much higher percentages are needed for sunny/hot days where more chlorine is consumer by the sun. I could set it high for all the time and not bother, but half the time it would produce way more than recommended FC range (easily 2-4x the ideal amounts).
 
what do you mean you "run hot"?
Slightly higher than target range. If the FC drifted above my target, but not below, I let it be. If I happened to catch it in the high teens, I'd shut it off and let it drift down, but it would usually stay in the 10-12 range.
 
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Slightly higher than target range. If the FC drifted above my target, but not below, I let it be. If I happened to catch it in the high teens, I'd shut it off and let it drift down, but it would usually stay in the 10-12 range.
I'll see if that works for me too. sounds like a good compromise.
 
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