Chlorine Lock

  • Last Post 28 May 2019
youngnet posted this 28 May 2019

 Help it has been over a week of opening inground 17K gallon pool. Pool Store said we have chlorine lock. Per store recommendation we have added 27 bags of Bioguard Burnout and still no reading on Chlorine. Prior to the 27 bags of burnout we drained down the pool about 3 feet and added fresh water. The numbers from the test saying we had chlorine block were:

PH 8.2 Free Chlorine 0.5 Total Alkanlinity 289 Total Chlorine 8 CYA 38 TSA 300 and Optimizer Plus 28
Hardness 96 Also said Combined Chlorine 7.5
We have a DE fliter and have backwashed numerous times at 20lbs torn apart the filter washed down the fins and started all over again. 2 times a day and still no luck. Thoughts, suggestions, please help. Thanks.

InyoRob posted this 28 May 2019

Your pH level and alkalinity levels are very high. The pH should be in the range of 7.2 - 7.8 and alkalinity should be 80-100 ppm. I'd recommend adding muriatic acid to lower those levels. 

The chlorine lock is usually caused by the CYA level being too high. However, 38ppm is on the low side.