Unexplained FC Consumption - it's back again

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T

toofast

0
May 9, 2013
993
North East Ohio
Well...here we go yet again- MOTHER TRUCKER (can I say that)

Cool spring, opened pool to perfect water, CYA was 20, (now 50ish) been dosing 2 PPM per day on Stenner and then adding manually as needed for conditions such as massive rains, etc.

I left on Monday AM, with a perfectly clear pool - I returned and JUST tested the water...my FC was O and my CC was O - *** - how is that possible ?

Left on Sunday PM with FC = 7 - dosed 2 PPM per day with Stenner...yet something ate my chlorine like mad in 3 days.

Pool was swam in Monday PM by my 5 year old for a few hours I was told and water was and still is clear with no signs of algae.

If you remember last year the pain I suffered....I am afraid it is starting all over again.

I just added enough bleach to push up to 7 PPM, I will test in an hour.

Last year I SLAMMED for nearly a month straight and then magically it fixed itself....so I hate to start SLAMMing again, till I see if this is a short term issue, since SLAMMing did not fix last year.

ONLY difference it started about a month from now...but honestly we heated the water up earlier this year. Is there any way that heated water (85 degrees) somehow starts a chemical reaction that somehow does something ?

OMG - do you guys all really want to go on this ride again this year ?
 
Re: Unexplained FC Consumption - SOLVED - although the Mystery Remains

On a side note, can a Moderator please update my thread title to "Unexplained FC Consumption - it's back again" or something like that. If you want me to start a new thread I could do that as well, although I would rather not if at all possible.
 
What I know...

My "chlorine" supply is good...just added enough to bring FC up to 7 PPM and it checked in Right at 7 PPM

So 5/13 - 3:15 PM FC=7 and CC=.5

I only pray this was a crazy anomaly...if there is anything else I should check just yell.
 
6 PM

FC = 9 (after stenner regular 2 PPM per day dose)
CC = .5

9 PM

FC = 8.5
CC = .5

Water cooled down 10 degrees though from Sunday - 86 - 76

Perhaps I jumped the gun and my 5 PPM per day since Sunday was just an freak ??

I think I will run the filter most of the night just in case, or does that not really matter ?
 
Yes I do understand that what makes me crazy is my chlorine use was dead accurate day or day now all the sudden it jumps to five parts per million..... Like you suggested I might simply be overreacting to last year's problem though..... I will continue to monitor closely
 
7:30 AM - and I passed the OCLT Test

FC- 7.5
CC-.5

It was 32 degrees last night though, so water is in the low 70's.

Only STRANGE thing is my CC is ALWAYS 0, and now it is .5 - since I chart thing daily (when not traveling) this is ODD to me.

Can algae be invisible and dormant at low temps and then at high temps it comes alive (still invisible of course)

I know you all think I am nuts, but normally my FC consumption is super consistent...and this just makes no sense.

I will continue to monitor closely and see what unfolds, my gut says I will be fine until the water temp rises again.

Remember, last year I passed the OCLT every time, my CC was never above .5, yet I was sucking down FC like a monster.
 

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Never lose track of just how simple this process is. Chlorine is consumed by two things only............ UV from the sun and organics in your pool water.

There is no other mystery......you have too much of one of those things (or a combination of those two, perhaps)
 
We're all crazy here, can't use that excuse! :) LOL

What is your CYA level? Couldn't find it. Lots of people are having difficulty this spring with all the rain, pollen and tree stuff. Me included.
 
Well the madness continues...

Water is super clear and I based OCLT the evening before...

Just for fun I run OCLT again, since I am home.

9 PM - FC = 9 / CC = .5
7 AM - FC = 7.5 / CC = .5

Same pattern as last year.

I always have a CC of .5 while this is happening....it never goes higher or lower then .5, but then it will clear, go back to 0 and my FC usage goes back to normal.

I got desperate this morning...sorry. My neighbor got rid of his pool and gave me his chemicals. Most were junk, but a nice new bottle of PhosFree. I am convinced I have some invisible alien living in my pool, perhaps all the farming around me is putting phosphates in my pool that he loves to eat. Gotta kill those phosphates I do.

I wonder if my local PB just by accident figured this out, as he INSISTED I MUST use PhosFree all the time to keep my pool clear, maybe he knows something we don't (by accident).

I am open to any further ideas...
 
So another member, mr. gunite is having similar issues...and I use the same RV Antifreeze ? Could he/we be on to anything ?

The post below is from him when we were trying to find common grounds between us.

Since pollen is organic, I would say it definitely consumes chlorine. However, even with heavy pollen, I can't say that chlorine would be getting consumed at 3 ppm per hour. I'd guess it'd be far less than that, especially in the case of crystal clear water and a filter that isn't in need of any backwashing.

I'm still thinking that my particular case is chlorine reacting with the propylene glycol in the RV antifreeze that got mistakenly injected into the pool water on opening. From the sources I've read, chlorine + propylene glycol = hydrogen. Since RV antifreeze is fairly hearty stuff, I'm thinking this is going to be a fairly long and drawn out process (weeks maybe) before they behave each other in my pool water.

I'm thinking of running some controlled chemistry experiments to see how rapidly chlorine gets consumed, if at all.
 
You can find out the chemical reactivity for thousands of common hazardous chemicals using the NOAA Chemical Reactivity Worksheet. However, that is referring to concentrated chemicals and tends to be very conservative (they even consider mixing water with sodium hypochlorite to be hazardous).

In general, the reaction of chlorine with alcohols is very slow, but it's faster for a secondary alcohol which is the case with propylene glycol (it has both a primary and a secondary alcohol). Hypochlorous acid may react with propylene glycol to form hydroxyacetone which then further reacts more quickly with chlorine to form glycolic acid and chloroform. This reaction will occur more quickly in acidic conditions so if you want to speed things up you might consider lowering the pH.

How much anti-freeze was used and was it 40% propylene glycol with 60% water? If you tell me that, then I can estimate how much chlorine it will take in total to get rid of the anti-freeze though in practice you just have to get through this unless you dilute with fresh water.
 

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