Extremely high FC

[phrantic09]

As part of our pool build, the company has someone come and clean the pool after the concrete decking is in. When they did this, the tech dumped between 2-3 jugs of liquid “shock” into the pool. Our pool is only 7855 gallons and our FC level is now 45. I’ve done the FAS/DPD test three times with the same result. Is this a good use case for chlorine neutralizer or should we just sit tight for the 10-20 days I expect it will take to burn off? Worries about damage to the liner and more importantly having a very expensive hole in the ground that I can’t use because of unsafe water.

CYA = 50
TA = 70
PH = who knows given the FC
Salt = 3000

 

[mgtfp]

I reckon it will come down much quicker than you think. If you have a cover, leave it off to let UV in, turn your SWG off.

Your CYA is a bit on the low side for an SWG anyway, you could bring that up to 70, and that would moderate the strength of the chlorine a lot.

Just make sure to then not let drop FC too low...

 

[phrantic09]

I reckon it will come down much quicker than you think. If you have a cover, leave it off to let UV in, turn your SWG off.

Your CYA is a bit on the low side for an SWG anyway, you could bring that up to 70, and that would moderate the strength of the chlorine a lot.

Just make sure to then not let drop FC too low...

Thanks,

I have the SWG off right now until we get to a reasonable level. I planned on bringing CYA up once these levels were down. The initial dose was done by the builder to the Jandy recommended level.

 

[phrantic09]

Okay- so now I’m not sure what is going on. The builder came and dumped a bunch of neutralizer in, PPM went to zero and has stayed that way even after having the SWG running at 100% for close to 24 hours. As far as I can tell it’s generating chlorine- bursts of bubbles are coming out of the returns and the controls aren’t indicating an error.

Going to let it run some more and if it stays at zero, will put in some bleach and see if that holds. No other changes to the chemistry than before. Hopefully don’t had a bad SWG, but don’t know how that could happen since it’s brand new.

 

[mgtfp]

He probably added way more than was needed. These guys don't calculate, they just dump. Now you have to add chlorine until it starts holding again before algae takes over.

I would have just waited, rather than playing yo-yo.

 

[mgtfp]

If you had added CYA straight away, then the high FC would have been moderated sufficiently to not do any damage to equipment. That's why I suggested it.

 

[phrantic09]

If you had added CYA straight away, then the high FC would have been moderated sufficiently to not do any damage to equipment. That's why I suggested it.

Thanks- I should have. Live and learn.

 

[SoDel]

Any idea what the PB used? Some can take several days before FC can rise especially if the water is cold. What I’m getting at is, if you add Cl but don’t get anything near the expected FC result, don’t necessarily just keep adding more. You might have to wait it out or a lot of Cl can be wasted.

 

[phrantic09]

Any idea what the PB used? Some can take several days before FC can rise especially if the water is cold. What I’m getting at is, if you add Cl but don’t get anything near the expected FC result, don’t necessarily just keep adding more. You might have to wait it out or a lot of Cl can be wasted.

No idea what was used. The water is 80 degrees. This morning I would dose the pool with enough to raise it to 10 and cranked the pump to 3000 and it was at zero an hour and a half later. I did this twice and also added enough CYA to get it to 70ppm. On the third dose, it was at 5 ppm 90 mins later so I put enough in to get it to 10 and we will see how it is when I get home.