Unexplained FC Consumption - SOLVED - although the Mystery Remains

[toofast]

Re: Unexplained FC Consumption (updated title)

That is a pretty pool!

I do wonder though................you say you are gone quite a bit............could some "friends" in the neighborhood be coming by to "check" out the pool?

Just an idea.

Kim

Well my wife is home and we lock the gate, and I have a camera and we have never caught anybody, but good idea for sure! And thanks for the compliment - with all these problems I sometimes lose site of all the positives!

 

[toofast]

Re: Unexplained FC Consumption (updated title)

Ok, another new bit of info....

I just read a post (can't find it again) from ChemGeek that suggested (I think) that excess FC burns off CYA. So, it sounds VERY POSSIBLE that since for over a month I have been injecting a TON of FC to try and overcome the zombie algae (that I still have) that that FC is eating all my CYA.

I seem to be in a maddening circle.

I have SLAMed for days on end, and somehow I still get a bit of algae growing at close to SLAM levels...INSANE!

Adding more stabilize to increase my CYA to at least 40 - afraid to go higher in case I have to SLAM again, but figured I would limp to 40 CYA and then figure it out.

Getting ready to head out on the road again, good news end of July I will be home for 5 days straight!

 

[DirtyRat91]

Re: Unexplained FC Consumption (updated title)

I played with some numbers for you, assuming the 40% loss to the sun that I predict a 30 ppm CYA level gives you.
Being SFC(Starting FC) DOSE(Added FC) = TFC(Total FC) - LTS(Loss To Sun (40% of TFC)) = EFC (Ending FC)
SFC +DOSE= TFC-LTS = EFC
12.5 + 5.5 = 18 - 7.2 = 10.8
10.8 + 5.5 = 16.3 - 6.52 = 9.78
9.78 + 5.5 = 15.28 - 6.11 = 9.17
9.17 + 5.5 = 14.6 - 5.87 = 8.73
Total added 22
Total lost 25.7

(Also this situation seems to go hand in hand with what you're actually experiencing, however you only dropped to 9.5 FC, not 8.73, so you may have a lower loss to sun / day, of perhaps 37% or so.)
This trend would continue until your Ending FC reached 8.25, then your dose 5.5, would send it to 13.75, and 40% loss would be 5.5, returning you to 8.25. Then it would remain at 8.25, only dropping below due to swimmers and added FC usage, or it would rise, due to overcast, less sunny days. Obviously it seems like your pool is a monster, using 25.7 FC in 4 days.

Similarly, the same math applied to a lower FC level, starting at 4 and dosing 1 FC per day.
4 + 1 = 5 - 2 = 3
3 + 1 = 4 - 1.6 = 2.4
2.4 + 1 = 3.4 - 1.36 = 2.04
2.04 + 1 = 3.04 - 1.21 = 1.83 FAIL! Below your minimum FC limit, algae blooms ensue!

Total added 4
Total lost 6.17

However your pool FC usage has only been 6.17 over 4 days. This is the same 40% loss to the sun, but running at the lower FC levels means the 40% loss is MUCH less.

Finally, dosing 2/day gives you...

4 + 2 = 6 - 2.4 = 3.6
3.6 + 2 = 5.6 - 2.24 = 3.36
3.36 + 2 = 5.36 - 2.14 = 3.22
3.22 + 2 = 5.22 - 2.09 = 3.13
3.13 + 2 = 5.13 - 2.05 = 3.08
.... etc until...
3 + 2 = 5 - 2 = 3

Finally you would reach equilibrium at 3 FC. Ideally you would have your 2 FC dosed all at once around 8 PM. Then, you'd maintain 5FC through the night, and much of the next day, where it would eventually drop to around 3 FC by 8 PM. You'd maintain a high FC level (per 30 CYA/Chlorine chart) for much of the day, and only have a usage of 2 ppm FC per day, which by anyone's standards is fine.


Again, I'm a noob, this is my theory. I like my theory, but of course I would. People with 30 CYA pools could give you more real life numbers, but I have a feeling I'm close.

 

[aussieta]

Re: Unexplained FC Consumption (updated title)

man, i am getting a headache
there are too many pages to keep referring back to now
how old are your test reagents and do you have access to another kit so you could verify your test results are accurate, by now i assume you have used up more than one set of reagents
i still think you should buy the CYA calibration solution, there is no way the sunlight is as bright in ohio as in florida one of my theories anyway
assuming the "zombie algae" is being reintroduced to your pool and not actually surviving in you pool stop using pool cover for a few days, assuming children have accidents in the pool is there a difference when pool is used versus no bather load, maybe close pool for 2 days and test regularly
looking at your recent pics at least you now have visible algae to account for fc loss
are there any forum members near you who could test your water and see if they are getting the same results as you, especially that CYA number, i am getting fixated on that i know
you don't want to waste this five day block so you need to try things you haven't been doing, if you keep going the way you are you will go back to work in the same position you are now, but more stressed
good luck

 

[aussieta]

Re: Unexplained FC Consumption (updated title)

just reading some other posts and singram mentions his/her chlorine values and toys, then mentions pool noodles
if your children have these that may be the hidden source of algae that is getting reintroduced,
the surface of noodles would be a great place for algae to grow

 

[toofast]

Re: Unexplained FC Consumption (updated title)

I played with some numbers for you, assuming the 40% loss to the sun that I predict a 30 ppm CYA level gives you.

Finally you would reach equilibrium at 3 FC. Ideally you would have your 2 FC dosed all at once around 8 PM. Then, you'd maintain 5FC through the night, and much of the next day, where it would eventually drop to around 3 FC by 8 PM. You'd maintain a high FC level (per 30 CYA/Chlorine chart) for much of the day, and only have a usage of 2 ppm FC per day, which by anyone's standards is fine.


Again, I'm a noob, this is my theory. I like my theory, but of course I would. People with 30 CYA pools could give you more real life numbers, but I have a feeling I'm close.

Ok, so makes sense to me...and I totally agree...however when this all started I was at lower levels (like you suggested) and added 2-3 FC per day kept dropping into the danger zone.

Then to make matters worse, I started with 40 CYA and was having similar issues. I would like to think that since my recent multi day SLAM and OCLT pass that al is well, but alas, I have slight algae growth at above 9 FC - HOW IS THAT POSSIBLE ?

- - - Updated - - -

man, i am getting a headache

how old are your test reagents and do you have access to another kit so you could verify your test results are accurate, by now i assume you have used up more than one set of reagents
i still think you should buy the CYA calibration solution, there is no way the sunlight is as bright in ohio as in florida one of my theories anyway
assuming the "zombie algae" is being reintroduced to your pool and not actually surviving in you pool stop using pool cover for a few days, assuming children have accidents in the pool is there a difference when pool is used versus no bather load, maybe close pool for 2 days and test regularly
looking at your recent pics at least you now have visible algae to account for fc loss
are there any forum members near you who could test your water and see if they are getting the same results as you, especially that CYA number, i am getting fixated on that i know
you don't want to waste this five day block so you need to try things you haven't been doing, if you keep going the way you are you will go back to work in the same position you are now, but more stressed
good luck

Reagents are all new...
I will purchase the CYA calibration solution, in the meantime I am adding more CYA to get up to at least 40 and then will test again against the solution.
What I am still blown away is how can algae grow 3 days after passing OCLT 2 days in a row and with FC well above the lower limit, i.e. 9 etc.

The issue MUST BE something is introducing algae over and over into the pool...and since no toys, etc. were in the pool it MUST be the cover, makes no sense, but I think it is time to throw away the cover.

 

[Kiss4aFrog]

Re: Unexplained FC Consumption (updated title)

If the solar cover is in good shape maybe just leaving it off and seeing if that cures the problem before you toss it. Have you had it on the pool so it can get treated with the higher FC while slamming ??

 

[SunnyOptimism]

Re: Unexplained FC Consumption (updated title)

What type of cover is it? Is the clear blue kind that looks like industrial grade bubble wrap? Or some other kind?


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[toofast]

Re: Unexplained FC Consumption (updated title)

Yes the cover is less than a year old it's a solar clear bubble like and has been on SLAM levels for extended times

 

[SunnyOptimism]

Unexplained FC Consumption (updated title)

Have you inspected the cover for bubbles that may have popped and possibly infiltrated with water?

Any stagnant water inside a bubble could be an algae source, albeit a small one.


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[buzzard302]

Re: Unexplained FC Consumption (updated title)

Well the cover is an easy variable to test. Leave that cover off for an extended period of time and see if it changes your results.

 

[kimkats]

Re: Unexplained FC Consumption (updated title)

Sunny! That is quite an idea! I wonder.......................oh my that may be it.

Kim

 

[SunnyOptimism]

Unexplained FC Consumption (updated title)

Sunny! That is quite an idea! I wonder.......................oh my that may be it.

Kim

It would be a nice way to end the story!

I have a bubble cover that my PB included with the pool build and practically never use it. He hates the things but I think AZ code now requires that he offers them as part of any new pool build. My pool is an irregular shape and I only have a limited amount of deck space so I really can't afford to put it on a reel. The few times I used it were a pain in the rear to put on and take off. The top would just get covered with debris and dead wild life and then all that crud would just fall into the pool no matter how carefully we tried to pull the cover off.

My cover now just sits in the corner of the yard all folded up for the lizards to make a home in....


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[SunnyOptimism]

Re: Unexplained FC Consumption (updated title)

TooFast,

Thinking about it further, it looks like you reel up your cover when home, then put it back on when you leave. Am I right?

If so, there is some drag-out water captured by the bubble cover that will stay stagnant in the roll there while reeled up. The FC in that little volume of water will dissipate quickly and then you'll have the perfect environment for bacterial and algae growth.

I say stop using the cover for a while and put your auto fill back on. Let your pool breath naturally while you're away and take the cover out of the equation entirely. Honestly, at this point, any water loss through evaporation is inconsequential compared to how much you've spent on chemicals so far trying to keep up with the FC loss.


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[toofast]

Re: Unexplained FC Consumption (updated title)

So got home for a day...

FC = 9.5

That is after I actually turned down the dosing like suggested...and the pool was spotless and no signs of algae (what else is new)

I closely inspected the cover, most of it looked pristine like this



However I had a few bubbles on the edge that looked like this, but is it really possible that this spec of algae in 2-3 spots could cause all my issues ? I will take it off, sanitize,etc..but just curious if this little amount could be my demons.

 

[SunnyOptimism]

Re: Unexplained FC Consumption (updated title)

Let me ask you something - why are you using the cover? Would it cost you anything to just leave it off for a week or so and see what happens?

I can't answer the question as to how many small specks of algae equals a problem, but we need to eliminate all possible sources. So I say clean the cover then roll it up and forget it for a while.


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[toofast]

Re: Unexplained FC Consumption (updated title)

Yes I will do.. .cover off

 

[toofast]

Re: Unexplained FC Consumption (updated title)

Getting ready to travel all week, cover is off (as of last night)

Just tested before my flight.

Yesterday at 2 PM: FC = 9.5 CC = 0
Today at 9 AM with no bleach added: FC = 8.0 and CC = 0

Now all of a sudden I am holding FC

I should mention, that many times through this "heck" - I had the cover off all day while my son/wife and myself were swimming, only to lose massive amounts of FC - so that I why I was so hesitant to believe it could be the cover.

Perhaps the cover was a contributor though - I will keep the cover off while traveling this week, then let's see what happens.

Bad news is now magically I might be "fixed" with no real reason why, which I hate!

 

[SunnyOptimism]

Re: Unexplained FC Consumption (updated title)

How much FC will you be dosing the pool with while you are away?

Is anyone going to do testing while you are away?


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[toofast]

Re: Unexplained FC Consumption (updated title)

How much FC will you be dosing the pool with while you are away?

Is anyone going to do testing while you are away?


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No one will be testing...

I was just working on how much I should dose.

I was thinking - since I am now at CYA of 40 - let's assume I lose 3 PPM per day, (which is still way higher than last year, but I don't want to have a green pool) PLUS I don't want to burn all my CYA with access FC (which MIGHT have been one of my issues).

So end of today I should be at 5, then I will add 2 PPM of FC to get back to 7, then I will be down to 4, so I will add 3 PPM, then down to 4 PPM, etc.

I think I will dose at the rate of 3 PPM of FC per day and then hope when I get back on Thursday that I don't have a green pool.

At least my wife can monitor and IF she see's any clarity change, she can dump in a gallon of bleach (at least I have her word she will try to help now)