Crystal clear. ..

[Pool_Fool]

22,000 gallon vinyl pool
Alk 60
Ph 7.2
Cal 250
Fc .5
Cc 0
Cya 35

What chemical could the pool store have put into the pool that could use up 19.5 ppm of FC in less than 3 hours at night?

There is not one sign of algae or bacteria in this pool and yet it will not hold FC. The store came by and rail roaded this guy, and then told him he was going to have to shock his pool to 80ppm. Suffice to say he told them to get lost not before they to got $650. He heard about me and asked me to check things out. Bean slamming for about a week now ti get rid of CCs, Ran the overnight test last night and results were less than stellar, as you can read.
The reason i believe they may have added something they shouldn't was their comment about shocking it and the cya being at 400 or something.
Anyway, truly the pool looks tremendous but chemically, not so good.

Thoughts?

Thanks
PF

 

[Divin Dave]

Maybe ammonia? That can occur from a wierd breakdown of CYA over the winter. We see quite a bit of that here this spring.
Pet store, aquarium section.. might be worth a shot.

 

[smackdab]

Maybe Alkyl Dimethyl Benzyl Ammonium Chloride which is a quatanery algaecide. The more that gets poured in the faster the chlorine will drop. Chlorine will eventially break it down.
Does the water foam?
Look in the skimmer and see if there is a black grease type substance at the waterline in the skimmer.
These are signs of ADBAC usage.

If he just opened the pool then it's probably ammonia from CYA breaking down like Dave said. Here is a thread Chem Geek started and worth reading.
http://www.troublefreepool.com/threads/6398-Opening-a-Pool-to-High-Chlorine-Demand-Ammonia

 

[pooldv]

What about antifreeze? Do you use it when closing?

 

[Isaac-1]

Remember MPS chlorine free shock shows up as CC on the FAS-DPD chlorine test, there is a special test for MPS that lets you account for it. As to the chlorine consumption, who knows, maybe they spiked it then added lots of chlorine reducer like Sodium Thiosulfate.

 

[Pool_Fool]

Thank you all for the tips.

Still no CCs and no FCs
I will assume to keep slamming, but in the meantime, when i go to the pet store, what am I looking for an ammonia test or remover?
Thanks all.

 

[Azgirl71]

You are looking for the ammonia test.

 

[Richard320]

Look for an Ammonia test kit at a pet store or aquarium place. Rumor has it Walmart sells one cheap. If the pool store sells one, it will no doubt be 3X as expensive.

 

[YoRgH]

What about antifreeze? Do you use it when closing?

Antifreeze have amonia?

 

[pooldv]

No, but it appears to consume chlorine trying to oxidize it. Here is a thread about it. http://www.troublefreepool.com/threads/93390-Antifreeze-and-Chlorine

 

[chem geek]

The difference is that the rate of chlorine loss, if from anti-freeze, is MUCH slower than what one would see with ammonia. With ammonia, the chlorine is consumed almost immediately (in minutes, depending on circulation) and turns into CC (monochloramine). Given how fast the chlorine was lost in the situation described in this thread, that sounds much more like ammonia than anything else.