I thought it might be good to continue this discussion in another thread since I have some new data to share.
Last year I ran a few measurements which indicated that a fixed voltage, variable amp bipolar SWG cell such as mine would produce chlorine at rates proportional to the salt level in the water. Although I would like to confirm with a few more measurements, I am pretty satisfied with the results and how it seems to match theory thanks to Richard's (aka chemgeek) explanations.
However, measurements I did were only at a couple different water temperatures and it showed a very modest change in chlorine production so I wasn't sure temperature was influencing the results. I had read several articles indicating the electrolysis was more efficient at higher solution temperatures so it would make sense that an SWG should produce more chlorine as temperature rises in the water.
I recently measured SWG chlorine production at various temperatures and saw a clear correlation to chlorine production. The first graph of the data below shows why some SWG manufactures will shut off an SWG at low temperatures. The slope of the curve is getting pretty steep there so it probably makes sense not to run the cell.
However, what I didn't expect was that the SWG had a peak production around 80 degrees and then started to roll off again at higher temperatures. Even though the amps increase linearly with temperature, the chlorine production was decreasing. However, based upon the chlorine gas solubility graph show on this page, it would seem the chlorine gas solubility goes down with increasing temperature which would explain the decrease in chlorine production.
What I find most interesting is that water temperature seems to have a larger impact than salt level. Although for a given water temperature, salt levels do make a difference. Just not as much as water temperature.
The bottom graph shows the chlorine production per amp which I think might be a good proxy for cell life although other factors probably come into play as well. There is a small correlation with salt level so a low salt level should impact cell life by only a small amount. However, there is a much higher correlation with water temperature. Since most SWG cells are rated in amp-hours, a very high or very low water temperature could affect cell life much more than the salt level. The higher temperatures being worse than the lower ones.
Note too that the SWG recommended salt levels are between 2700 and 3600 ppm. So the 2600 ppm test was below recommended levels.
SWG Chlorine Production vs Salt Level and Water Temperature
SWG Chlorine Production per Amp vs Salt Level and Water Temperature