I have a Jandy Aquapure PLC-1400 chlorine generator system, and I'm puzzled by the salt level readings I've been getting.
Before I added salt (see below), the SWG display reported the salt level is 3,000ppm. It was 3300ppm, which is about where I normally keep it, but then we finally got a a couple of inches of rain and I took advantage of that to backwash the sand filter.
But, then I took a water sample to Leslie's pool supply,and they told me the level was 2300. When I told them my Aquapure says it's 3,000, they said the salt level they measure is frequently incorrect but couldn't say why. That's not terribly helpful, especially since I don't believe the salt level is something that changes if the pool water sits in a plastic bottle for an hour or two.
So then I bought some Chlorox salt test strips from Lowes, and those are completely useless. They say 900ppm and take forever to give me a reading. They have a scale on the strip and you have to let them soak in the water for some time. Oddly enough, the scale on the strip reads 3,000 but the instructions provide a conversion table and that converts to 900. I called their tech support to ask why they can't just print the ppm on the strip (which would be correct for me) and they said that the conversion factor changes for each production run of strips. Alrighty then.
So, I finally ordered one of the salt concentration tester thingies pictured below from Amazon -- it's about $30 and claims to be for salt water pool level-testing. Lo and behold, it reads about 2500pm. I dipped it in a number of places around my pool and spa and it always comes up with about the same result, +/-10ppm.
Because 2500ppm is a bit below the threshold of 2600ppm that I was taught in "pool school" but 3000ppm is comfortably away from the upper limit, I added two bags of salt, turned off the cell, and let it mix for 24 hours. Now the built-in salinity sensor says 3600ppm and the tester says 2850ppm. I noticed before that each bag of salt increases the salinity by 150 to 200ppm when it's in-range so neither is wildly off. It's the baseline that seems to be off.
I'm going to ask my lovely pharmacist wife to mix a 3000ppm salt solution (let her do the math) and then test this sensor and the salt strips.
Also, I just cleaned the salt cell yesterday after 18 months of service -- there were some small calcium blobs and a little bit of scale on one end where the electrodes are, but the acid bath completely dissolved that and it looks brand new again (color me relieved as I'd been putting this off). The thing can make a lot of chlorine -- when I run it at 50%, the chlorine level shoots up to 8-10 (verified with strips and liquid) so I had to back it off to 25% which gives me 3-5. While I had the salt cell apart, I also mildly sand-papered the electrodes on the flow sensor. The salt level readings didn't change.
So, is the Jandy salt sensor just not to be trusted? I am not aware of any calibration procedure.
Before I added salt (see below), the SWG display reported the salt level is 3,000ppm. It was 3300ppm, which is about where I normally keep it, but then we finally got a a couple of inches of rain and I took advantage of that to backwash the sand filter.
But, then I took a water sample to Leslie's pool supply,and they told me the level was 2300. When I told them my Aquapure says it's 3,000, they said the salt level they measure is frequently incorrect but couldn't say why. That's not terribly helpful, especially since I don't believe the salt level is something that changes if the pool water sits in a plastic bottle for an hour or two.
So then I bought some Chlorox salt test strips from Lowes, and those are completely useless. They say 900ppm and take forever to give me a reading. They have a scale on the strip and you have to let them soak in the water for some time. Oddly enough, the scale on the strip reads 3,000 but the instructions provide a conversion table and that converts to 900. I called their tech support to ask why they can't just print the ppm on the strip (which would be correct for me) and they said that the conversion factor changes for each production run of strips. Alrighty then.
So, I finally ordered one of the salt concentration tester thingies pictured below from Amazon -- it's about $30 and claims to be for salt water pool level-testing. Lo and behold, it reads about 2500pm. I dipped it in a number of places around my pool and spa and it always comes up with about the same result, +/-10ppm.
Because 2500ppm is a bit below the threshold of 2600ppm that I was taught in "pool school" but 3000ppm is comfortably away from the upper limit, I added two bags of salt, turned off the cell, and let it mix for 24 hours. Now the built-in salinity sensor says 3600ppm and the tester says 2850ppm. I noticed before that each bag of salt increases the salinity by 150 to 200ppm when it's in-range so neither is wildly off. It's the baseline that seems to be off.
I'm going to ask my lovely pharmacist wife to mix a 3000ppm salt solution (let her do the math) and then test this sensor and the salt strips.
Also, I just cleaned the salt cell yesterday after 18 months of service -- there were some small calcium blobs and a little bit of scale on one end where the electrodes are, but the acid bath completely dissolved that and it looks brand new again (color me relieved as I'd been putting this off). The thing can make a lot of chlorine -- when I run it at 50%, the chlorine level shoots up to 8-10 (verified with strips and liquid) so I had to back it off to 25% which gives me 3-5. While I had the salt cell apart, I also mildly sand-papered the electrodes on the flow sensor. The salt level readings didn't change.
So, is the Jandy salt sensor just not to be trusted? I am not aware of any calibration procedure.
