Higher FC than planned

[YesRushGen]

So, following our liner replacement project...

Liner Replacement Project

...I'm now getting the new fill water all dialed in. First was to get some CYA and Chlorine going. I verified there was zero FC after about 30 minutes of water circulating.

I manually added 3 jugs of the Pool Essentials Chlorine product, 10% concentration that alot of folks have been using. For my pool size, that should have raised FC by about 9.0. However, after about an hour of circulation, my test showed FC 14.0/CC 0.5. Where did the extra 5.0 come from? Is it possible my product had GREATER than 10% concentration?

It gets better - this morning to perform an OCLT my test showed FC 16.0/CC 0.0.

I will also note that my SWG is not even hooked up, so there couldn't be any additional from there. My DPD powder is brand new, and the reactants are two years old (stored under absolute ideal conditions - every test this year has been as expected, until now)

What in the world???

 

[cfherrman]

Yes, often bleach is shipped higher than labeled especially in the higher % bleach.

As long as you have cya going your fine

 

[YesRushGen]

Thanks,

Based on added amounts I should be up to about 50-60 CYA, ultimately targeting 75.

So yeah, the overnight increase is what trips me up. I guess I'll just keep monitoring and hookup/activate my SWG once I get down to FC5-6.

 

[PoolGate]

I suspect you have over-estimated your pool volume.

 

[YesRushGen]

Well isn't that interesting... I just did a "reverse salt calculation" and came up with approx 28,000 gallons for my pool. I added 800lbs and I'm at 3400ppm, which implies approximately 28,000.

What's strange is that prior to the liner replacement, I'd been using 33,000 in all the PoolMath calcs and things were always spot on. I figure some of the vermiculite patch work could reduce the volume by some amount, but by 5,000 gallons?!?!

Regardless, the math doesn't lie - I'll be using 28,000 in my calcs from here on.

 

[wjr75]

Do you have a speed stir? This really helps in the mixing... maybe that was the difference in your readings??

 

[YesRushGen]

I actually did get the speed stir a couple years ago. I'm embarrassed to say I never even opened it. :silent:

 

[cfherrman]

Might be off with salt because your water has salt in it before adding

 

[wjr75]

Must open the speed stir!!

 

[YesRushGen]

I did open the speed stir, just tonight, I love it!!!