Suggestions on dealing with Heterotrophic Plate Count (hpc)

[jethbrown]

New member but working on pools for some time.

We have a indoor salt water pool.

Lately we have had a High Plate count, and have failed the lab tests. We have shocked the pool the first time to 10 PPM, and failed again. I then shocked it with Lithium Shock to 20 ppm and again failed. Drained pool partially and refilled with fresh water, along with shock treatment and were still getting the plate count issues. There are no coliforms present on the lab results. Latest plate count was 1140 CFU/ml acceptable is 100 or less.

Rather then drain the entire pool, close the facility for 3 days to do it, due to reheating the water, any suggestions on how we can combat this?

Pool Data;
volume 67585 Liters
Acutrol Pool Controller
Autopilot Lectranators x 2
Sand Filters x 2
Temperature maintained is 29-30 Celsius

Salt water maintained at 3400 ppm
Ph setpoint is 7.3, maintained by acid tank and pump
Pool has Wapotec System added on, Hydosan, Hyrdoxan and KlearFloc (coagulate)
ORP setpoint is 750

FCL averages between 0.60 and 1.2, TCL is around 2.85 on average.

 

[JasonLion]

Welcome to TFP!

Understanding what is going on starts with a getting all of your water test results together. I am particularly concerned with what your CYA level is.

For an indoor pool, ventilation is also important. And a good description of what the water looks like and what chemical you normally use for chlorine will also help.

 

[zea3]

I read through a couple of articles to get a better understanding of HPC. Do you have a ordinance in place that sets a limit on how high the HPC is allowed to rise? Did you test the fill water for HPC?