Definitely a mystery.
All you can do is lower the pH enough to keep the CSI under control.
All you can do is lower the pH enough to keep the CSI under control.
Impact of rain on ph
- Thread starter Ahultin
- Start date
- Aug 19, 2021
- 1,605
- Pool Size
- 17700
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I beleive something is leaching in with rain just don't know what. 
I added 25oz 31.45 ma at 3pm yesterday then checked ph at @4:45 and it was 7.77. We had more rain last night and just logged pH at 8.04. As the csi is in range (-.19) I'm going to leave it for now and recheck tomorrow. Intelliph is still dispensing at 8% hourly and no more rain is expected until Thursday.
I added 25oz 31.45 ma at 3pm yesterday then checked ph at @4:45 and it was 7.77. We had more rain last night and just logged pH at 8.04. As the csi is in range (-.19) I'm going to leave it for now and recheck tomorrow. Intelliph is still dispensing at 8% hourly and no more rain is expected until Thursday.
- May 23, 2015
- 25,740
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I suggest disabling the IntelliPH when it’s raining and waiting until the rain stops and you can manually rebalance the pool. Probes can get wonky when the system isn’t at equilibrium and you could inadvertently add more acid than is needed. Honestly, chasing pH is a fool’s errand. Your pool isn’t going to turn into a black hole of algae and swallow up the universe just because the pH isn’t exact. Let the rains pass and the water mix, use a manual test kit to get good readings and then adjust from there incrementally. Then, once the chemistry is where you want it you can let the automated feeders go back into service.
- Aug 19, 2021
- 1,605
- Pool Size
- 17700
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
- Aug 19, 2021
- 1,605
- Pool Size
- 17700
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Intelliph is strictly time based, no probes. I have adjusted its output as needed and it worked without outside ma until this weekend when pH spiked above 9 ove night. I had been testing pH and fc ~every other day and full test weekly. With the rains and the visible change to water clarity I've been testing daily.
Any added base will increase the TA.
pH rise with no associated TA increase will be from aeration and loss of carbon dioxide..
Aeration should stop increasing the pH at about 8.3, so the results are definitely puzzling.
- May 23, 2015
- 25,740
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I really would not do any kind of daily adjustments to the chemistry until the rain passes. We had a few days of rain here, remnants from CA, and basically all I did prior to the rain was drop the pH/TA a bit and then added a gallon of 10% LC. It’s been 2 days and I probably won’t bother testing again for another day or so. During that time the water clarity changed a bit with the rain but it’s just transient. There’s no point in fiddling with the chemistry as it will be fine for a few days.
My point is simply to not waste effort on transient phenomena like pH and rain because there are so many variables that will come into play that you can’t possible account for all of them accurately.
My point is simply to not waste effort on transient phenomena like pH and rain because there are so many variables that will come into play that you can’t possible account for all of them accurately.
Last edited:
- Aug 19, 2021
- 1,605
- Pool Size
- 17700
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Understood thank you, reality is this is my first wet season with the pool and the first event that significantly impacted clarity and chemistry. I did not want this to be the event that brought out the "I told you to hire somebody you cheap *******" from my wife
Hi,
I used to calibrate measuring instruments for a living. pH probes are not that accurate and as a logarithmic scale the difference between a pH of 7 and 8 are very small and hard to measure.
I have digital pH meters at home that I use for brewing beer - Like you I have calibrated them to a known solution, then tested in distilled water and seen it correctly, but then put it in my pool and it is incorrect. This is even a fancy meter with temperature adjustment.
The best way to measure pH is to ensure the water is adequately mixed (which is should be running the pump 21 hours a day) and then using a chemical reagent that measures between 7.2 and 7.8. pH above 7.8 will just just as 7.8. If it's been raining a lot just take the sample down from as deep as practical.
Unfortunately I am new to pool ownership and cannot suggest a good way to get pH in order again. But I am experienced in water chemistry and measuring instruments and will say that a pH reagent test is what you need and not to trust the probes. I worked at Australia's largest electricity producer for a period of time as well and shared a room with the water chemists. They looked after the water in the turbine and like pool ownership it needed a very specific chemistry. They had very expensive and fancy digital pH meters but all of them used manual chemical reagent tests instead.
I used to calibrate measuring instruments for a living. pH probes are not that accurate and as a logarithmic scale the difference between a pH of 7 and 8 are very small and hard to measure.
I have digital pH meters at home that I use for brewing beer - Like you I have calibrated them to a known solution, then tested in distilled water and seen it correctly, but then put it in my pool and it is incorrect. This is even a fancy meter with temperature adjustment.
The best way to measure pH is to ensure the water is adequately mixed (which is should be running the pump 21 hours a day) and then using a chemical reagent that measures between 7.2 and 7.8. pH above 7.8 will just just as 7.8. If it's been raining a lot just take the sample down from as deep as practical.
Unfortunately I am new to pool ownership and cannot suggest a good way to get pH in order again. But I am experienced in water chemistry and measuring instruments and will say that a pH reagent test is what you need and not to trust the probes. I worked at Australia's largest electricity producer for a period of time as well and shared a room with the water chemists. They looked after the water in the turbine and like pool ownership it needed a very specific chemistry. They had very expensive and fancy digital pH meters but all of them used manual chemical reagent tests instead.