I just opened my 18,000 gallon pool and shocked with 4 gallons of liquid chlorine. FC was 1ppm and CC was 6ppm. Pool store said to add 18lbs of oxysheen. Now my FAS/DPD test is showing 14ppm FC. But my OTO test is still showing 1ppm. Does oxysheen cause the FAS/DPD test to show high FC levels? Do I need to shock my pool with liquid chlorine again?
Chlorine testing after adding Oxysheen
- Thread starter CCpoolnewbie
- Start date
Welcome to TFP.
Oxysheen is non-chlorine oxidizer so you can't use either test to measure it.
You should continue shocking with liquid chlorine.
Oxysheen is non-chlorine oxidizer so you can't use either test to measure it.
You should continue shocking with liquid chlorine.
I believe Oxysheen is MPS and will show up as CC in the FAS-DPD test. What it does in the OTO test I do not know.
I found this online: CAUTION: Oxidizers other than chlorine (OxySheen and other products containing peroxymonopersulfate) will react with DPD #3. So evidently, it is interfering with my DPD test.
Took a sample in to a different store this morning and my levels were still high - 1.9ppm FC and 8.1ppm CC. They gave me 2lbs of Oxybrite (same thing - 43% peroxymonopersulfate) and told me to come back in a day or two and test again. But looking around online it looks like I need to add 2lbs of Oxybrite or Oxysheen per 10,000 gallons of water per CC ppm. This would mean another 30lbs! At $8/lb, this would be $380 of oxidizer in the first 3 days of opening my pool. Sounds excessive. Anybody have other ideas?
Took a sample in to a different store this morning and my levels were still high - 1.9ppm FC and 8.1ppm CC. They gave me 2lbs of Oxybrite (same thing - 43% peroxymonopersulfate) and told me to come back in a day or two and test again. But looking around online it looks like I need to add 2lbs of Oxybrite or Oxysheen per 10,000 gallons of water per CC ppm. This would mean another 30lbs! At $8/lb, this would be $380 of oxidizer in the first 3 days of opening my pool. Sounds excessive. Anybody have other ideas?
Absolutely! Shock your pool with chlorine. Do so by following the article in Pool School and it will be cheaper than MPS and totally predictable.
Thanks Dave.
I haven't been able to get the FC to stay at shock level yet. I read a rule of thumb to shock by raising the FC to 10 times the amount of CC, which means I would have to get my FC up to 81ppm. I was worried this is bad for the pool, so the store recommended non-chlorine shock instead. So it sounds like you're recommending to add two gallons of shock twice a day until the CC is gone? Or do I need to add 12 gallons all at once?
I haven't been able to get the FC to stay at shock level yet. I read a rule of thumb to shock by raising the FC to 10 times the amount of CC, which means I would have to get my FC up to 81ppm. I was worried this is bad for the pool, so the store recommended non-chlorine shock instead. So it sounds like you're recommending to add two gallons of shock twice a day until the CC is gone? Or do I need to add 12 gallons all at once?
FC level should be a function of CYA, not CC. There is a CYA/FC chart in Pool School that will tell you what FC level you should target.
The whole shocking to 10x CC story is a myth, commonly repeated but not true.
Non-chlorine shock will work, but it is more expensive than chlorine and has no particular advantages in this situation.
How much chlorine you add at one time depends on your CYA level. You can add more chlorine as frequently as once per hour.
Non-chlorine shock will work, but it is more expensive than chlorine and has no particular advantages in this situation.
How much chlorine you add at one time depends on your CYA level. You can add more chlorine as frequently as once per hour.
Great! Thanks. I haven't added any CYA yet. Is it okay to wait until after I shock it? I assume 10ppm FC should be sufficient since that is the lowest in the CYA/FC chart. I just don't know how much chlorine to add each time. According to the bottle, 180oz. should be enough to raise the FC by 10ppm, but I haven't been able to get it that high.
It is good, though not completely essential, to have some CYA in the water when shocking. Without CYA you lose chlorine to sunlight more quickly than to cleaning up the water. You can get by without CYA by adding most of your chlorine in the evening, when sunlight isn't an issue, but raising CYA to around 30 is a better solution.