SWG output vs pump time

[Crunchy]

Happy Friday

Until recently I ran the pump for 2x3hr sessions per day for total 6hrs per day, the SWG was set at 50%.

Consistently getting FC results 6.8 to 7. I wanted to drop this to 5 so I set a new regime at 1x 3 and 1x2 for a total 5 hrs per day with SWG set at 100% expecting that dropping 1 hour pump time per day and increasing SWG from 50% to 100% would pretty much cancel each other out. However within 2 days the FC dropped from 7 to 4.8, my question is......does pump time have a far greater impact on chlorine product than output setting? Perhaps something like FC=0.8PT + 0.2OP where PT = pump time and OP=SWG output?

thanks
Crunchy

 

[JoyfulNoise]

That is odd. Your chlorine output setting actually increased from 3 hours of on-time to 5 hours of on-time so you should have seen an increase in FC. It should make no difference in chlorine production if you use 4 hours at 50% or 2 hours at 100% unless there's something unusual about how your cell measures it's duty cycle. Most manufacturers have a set measurement time (ex, 60 minutes) and then the output controls how much of that time the cell is ON for. I don't think we have PuraFlo in the US unless it's manufactured here and branded under a different name in Australia.

One thing to do as a sanity check is to perform and Overnight Chlorine Loss Test (OCLT) to make sure there isn't something growing in your water. The article isn't specific about how much FC to add at sunset and implies it should just be whatever your target value is. I like to raise my FC to a minimum of 10ppm when doing an OCLT so that I can get a better measure of the loss but others do it differently. If the water has biological or organic contamination, the loss should be pretty obvious.

Finally you can pull the cell to see if it has started scaling. Running the cell at 100% means that the unit will constantly produce chlorine thus leading to lots of aeration inside the cell as well as much higher pH than the bulk pool water. This can lead to greater scaling rates than running the cell in a more intermittent fashion (eg, a 50% duty cycle). So checking the cell for scaling is important especially since you've reported calcium flaking in a previous post.

 

[Crunchy]

I ran 2 by three hour sessions per day so total of 6 and roped it to 5, surprised how fast the Cl dropped. Thanks for the advice might go back to 50% and longer pump time again.