I have the PoolPilot Total Digital with ORP. The problem I find with ORP is that it swings the Free Chloine level (FC) around too much depending on the weather, sunny, overcast, or very dark clouds. This might be due to the fact that when the Sun is out it is very strong, as we live in Honolulu, and when it is dark it is very, very, dark. Our pool is 10,000 gals with an SC-60.
I have to agree with others that ORP is not the best way to set a SWG pool, interesting to know the number but not that useful in controlling FC levels,
Target FC in both my Pool and my friends is 4.6 to 5.0. Our pools are crystal clear and for once his dogs have no skin rashes at this level and they swim daily. They are very happy with this level (CyA is 30) as they have literally spent thousands on having these rashes treated and now no longer appear. I suffer from ear infections, very common in Hawaii even among the young due to the humidity year round, I no longer get these infections so I to am happy at this FC level. This gives an approximate HOCl (as ppm Cl2) level of 0.077.
I help my friend with their pool and he has an Aquapure 1400 and a 20,000 gal pool. He has no ORP function and the pool is set at 90% for 8 hours (and yes I know 90% is very high). His chlorine maintains the same level day in day out, give, or take, a very small fluctuation.
The great thing about the PoolPilot is that it can switch from production % to ORP. I now switch to ORP only when we need to impress people who come over, these include but are not limited to attorneys and some doctors.
As electricity here is around .35c a kilowatt, I try to run the pool for 4 ½ hours giving it a 1 ½ times turn.
Both pools lose on average 2.2 ppm FC per day. I created a spreadsheet based on chlorine production in lbs at specific power settings, 1, 2, and 3.
My assumption is that it needs 0.267045471 of an oz to create 0.2 FC per 10,000 gals. I hope that is correct, please correct me if I am wrong in this assumption.
With the aim of maintaining a more consistent FC level, the unit is currently set at 64% at power level 2, if set at Power Level 3 it would be around 51%. As the acid feeder needs to catch up to the chlorine production, is it better to keep it at 64% at power level 2, or to increase it to power level 3 at 51%? Or should I increase the run time; something I do want to do as it will up my electric bill?
Which of the two Power settings at these different levels would give the cell the longest life or would it be the same? Final question is how many "On Hours" is an SC-60 cell expected to last for?
ChemGeek, if you would like me to send a copy of the spreadsheet file please PM and send me your email. I am sure you can improve upon it. It offers a slightly more accurate way to get the setting right first time (I think and hope). It also allows one to evaluate different SWG units and their sizes versus the size of pool and their desired pump run times. This might be useful for first-time buyers or users. As I am no programmer the spreadsheet is a work in progress but I think it is fairly accurate, but am not sure.
Please note: I am only willing to send the spreadsheet to ChemGeek as I believe he will know what to do with it. To others please do not request or PM me as I do not have the time to reply. Thank you.