Millon Dollar Idea......?


Well-known member
Oct 8, 2015
San Diego, Ca.
Why don't SWG manufactures (Pentair/Hayward) automate their SWG's to the point where a sensor reads the FC level and adjusts the output based on that reading and a preselected FC level?
The Pool Owner wouldn't have to manually adjust it as the climate changes.



Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
Like Mark said, some try to so this with ORP sensors, but they are not reliable, especially in outdoor pools with the CYA levels we recommend.

No one has come up with a way to read the FC directly.


TFP Expert
Mar 2, 2011
Probably not a viable solution for residential pools. There are several manufacturers of free chlorine sensors. I don't think that they would be affordable for at least several years as the sensor technology decreases in cost. It would he nice to have.

Beyond the initial cost is ongoing maintenance which would cost quite a bit of time and money. For now, FASDPD is the best method.


TFP Expert
Apr 19, 2013
Sacramento, CA
The problem with all the auto sensors is they require regular calibration. In addition the Hatch sensor, which basically uses the differences in conductivity of the water to derive a chlorine concentration, is sensitive to changes in ph and temperature. In short its readings can vary depending on the ph or temperature of the water. If you have a situation with constant temperature and ph then you can rely on the result, if you don't have that situation then its more problematic.