Hi,
We are having a peculiar issue at our aquatic facility with one of our pools. As of November of this past year we have started seeing combined chlorine levels of no lower than 0.2 PPM. It's not unusual for it to spike up to 0.8 PPM even. In an effort to remedy this issue we have shocked the pool several times in the past month. We have shocked it to break-point for 12 hours, 16 PPM FAC for 18 hours, and even 20 PPM FAC for over 24 hours. The next time the water is tested before the facility is opened we will still find a combined chlorine reading of 0.4 PPM, 0.6 PPM, or even 0.8 PPM still. We do have a Hanovia UV system installed that unfortunately stopped working in early December that will be replaced in the coming weeks. Looking back at our test logs, even when the UV system was operating normally we still had chlorine splits. I have also asked that our staff stop using non-chlorinated shock to rule our potential interference with the FAS-DPD test - this still has not shown improvements.
Our local pool store across the road has tested our water multiple times using the same test kit that we use and has explained to us that there's no CC reading at all. Which is strange as they're using the same kit, and preforming the test identically to how we would. We took a water sample to another pool store out of town that uses a computerized system for testing and they have found there to be a 0.6-0.8 split as expected. Strangely, they informed us that unless our CC level is above 2.0 PPM there's no need to shock. I spoke with several people at the store including service managers, and they all agreed that 2.0 PPM or above is the action level.
Confused, and dumbfounded we re-examined every single thing we do to test the water. Sanitizing our test kits, using brand new reagents, sampling from different locations around the pool, testing our fill water, making sure we are preforming the test exactly the way Taylor has explained. Nothing. Still high combined chlorine. Does anyone have a hunch on what may be the cause of this, and how we could effectively lower our CC?
Here's a little info about the pool in question:
Indoor/Outdoor: Indoor
Capacity: 88,000
Surface: White concrete w/marble dust, and blue quartz aggregate
Sanitizer: Pulsar Plus Cal-Hypo briquettes
Shock: Pulsar Plus Power Shock (79%)
pH control: Co2 feed, and/or muriatic acid
TA control: Soda ash
Turnover Rate: 3.5 hours
Features: Dumping buckets, arch jets, gusher fountain, water slide, zero entry
Occupancy: Typical weekday sees probably 50-100 swimmers, weekend around 100-200
Backwash frequency: Once a week
Filter type: 31 FT sand filter
Typical chemistry:
FAC: 2.0 PPM
CC: 0.6-0.8 PPM
TC: 2.6-2.8 PPM
pH: 7.3-7.5
TA: 100
CH: 300-500
CYA: 0
We are having a peculiar issue at our aquatic facility with one of our pools. As of November of this past year we have started seeing combined chlorine levels of no lower than 0.2 PPM. It's not unusual for it to spike up to 0.8 PPM even. In an effort to remedy this issue we have shocked the pool several times in the past month. We have shocked it to break-point for 12 hours, 16 PPM FAC for 18 hours, and even 20 PPM FAC for over 24 hours. The next time the water is tested before the facility is opened we will still find a combined chlorine reading of 0.4 PPM, 0.6 PPM, or even 0.8 PPM still. We do have a Hanovia UV system installed that unfortunately stopped working in early December that will be replaced in the coming weeks. Looking back at our test logs, even when the UV system was operating normally we still had chlorine splits. I have also asked that our staff stop using non-chlorinated shock to rule our potential interference with the FAS-DPD test - this still has not shown improvements.
Our local pool store across the road has tested our water multiple times using the same test kit that we use and has explained to us that there's no CC reading at all. Which is strange as they're using the same kit, and preforming the test identically to how we would. We took a water sample to another pool store out of town that uses a computerized system for testing and they have found there to be a 0.6-0.8 split as expected. Strangely, they informed us that unless our CC level is above 2.0 PPM there's no need to shock. I spoke with several people at the store including service managers, and they all agreed that 2.0 PPM or above is the action level.
Confused, and dumbfounded we re-examined every single thing we do to test the water. Sanitizing our test kits, using brand new reagents, sampling from different locations around the pool, testing our fill water, making sure we are preforming the test exactly the way Taylor has explained. Nothing. Still high combined chlorine. Does anyone have a hunch on what may be the cause of this, and how we could effectively lower our CC?
Here's a little info about the pool in question:
Indoor/Outdoor: Indoor
Capacity: 88,000
Surface: White concrete w/marble dust, and blue quartz aggregate
Sanitizer: Pulsar Plus Cal-Hypo briquettes
Shock: Pulsar Plus Power Shock (79%)
pH control: Co2 feed, and/or muriatic acid
TA control: Soda ash
Turnover Rate: 3.5 hours
Features: Dumping buckets, arch jets, gusher fountain, water slide, zero entry
Occupancy: Typical weekday sees probably 50-100 swimmers, weekend around 100-200
Backwash frequency: Once a week
Filter type: 31 FT sand filter
Typical chemistry:
FAC: 2.0 PPM
CC: 0.6-0.8 PPM
TC: 2.6-2.8 PPM
pH: 7.3-7.5
TA: 100
CH: 300-500
CYA: 0
A couple items to highlight before we go too far in this thread .... one - We emphasize accurate pool owner testing with a TFP-recommended test kit (TF-100 or Taylor K-2006). We give very little credence to any pool store testing. The other item is that you are in the industry and operating what appears to be a commercial pool, so you probably have some local issues to contend with there as well. But I'll start off with some basic TFP items.
