Double chlorine dose in pool

What is floc, clarifier, stabilizer, cyanuric acid,
algaecide, brightener, dichlor, sodium hypo,
sodium bisulfate, ....??
Pool Newbie
Pool Newbie
Posts: 1
Joined: Thu 03 Jun, 2010 21:34
My Pool: Intex 18' x 52" circular above ground. 6,981 gal.
Krystal Clear Model 633T Filter Pump 110 - 120 V, pumps 2500 gallon per hour.
Location: Florida

Double chlorine dose in pool

Postby twinstb » Thu 03 Jun, 2010 21:54

2.5 gallons of chlorine was just put in my 7000 gallon capacity above ground pool instead of 1 gallon. Will this damage my pool. What should I do (or can I do) to correct this and bring levels down? 1 gallon of Suncoast Muriatic Acid and 1.6 lbs stabilizer was also put in the pool. Pool is an Intex 18' x 52", 7000 gal circular pool w/Krystal clear Model 633T pump. 110-120 V, pumps 2,500 gph.

chem geek
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Location: San Rafael, California

Double chlorine dose in pool

Postby chem geek » Fri 04 Jun, 2010 21:19

You didn't specify the type of chlorine you added. If it was 12.5% chlorinating liquid, then this would raise the Free Chlorine (FC) in your 7000 gallon pool by about 45 ppm which is high. If it was 6% bleach, then it would raise the FC by about half as much.

The CYA in the water will help to moderate chlorine's strength, but it was still a high level of chlorine. If you have sun on the pool at this time of year where you live, then just expose the pool to sun all day which should bring down the FC level, perhaps in half, over a day, depending on the CYA level. If you wanted to bring it down in a hurry, then you could use a chlorine neutralizer such as sodium thiosulfate, but I think you are OK just exposing the pool to sunlight to bring it down a lot in just one day.

Of much greater concern is the Muriatic Acid that was added. If it was full-strength 31.45% Hydrochloric acid, then the pH could have been brought down below 6 which can dissolve plaster surfaces and is bad for vinyl (so your Intex pool) and corrode metal such as in a heat exchanger in a gas heater and is bad for pump seals as well. I would get the FC level to drop first over one day since the pH will have risen from the chlorine and the pH test won't be accurate when the FC is too high, then start raising the pH back up to above 7 (7.5 is ideal).

The 1.6 pounds of CYA raised the CYA by 27 ppm which isn't too high (though could be too low overall depending on what you started with).

In the future, use The Pool Calculator to calculate dosages.

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