AprilH,
Just to be clear, ORP voltage is used as a proxy for free chlorine concentration. In theory, the measured ORP voltage should decrease with decreasing FC. However, in practice, there are so many other variables to your pool water (pH, CYA, TA, etc) that also affect the ORP voltage signal that it can make it difficult to figure out what is really happening. A salt water pool only confounds the problem further by adding another variable to the system, namely salt concentration as measured by a proxy value called TDS (total dissolved solids). Can these things be measured and controlled? Sure. But when your pool water goes out of whack, you'll be the one to debug all these things so keeping it simple up front will make your life a lot easier.
pH probes are similar to ORP probes but are a little less sensitive to all the "noise" generated by the other pool water parameters.
That was the basis of my recommendation to you that you consider only using a a time-based acid dispensing system. Pentair sells the IntelliPH system that many in this forum have successfully installed as DIY projects and I'm sure Hayward has something similar. Using a time-based system is ultimately much easier to understand and debug as all you have to do is adjust the dispensing time up or down to lower or increase your pools pH. Believe me, your pH isn't going to change second by second. pH swings in most well balanced pools happen over days and weeks, a time frame well within your ability to get a handle on, test and control.
And I do believe your dad is/was a very wise man....and one more tip - if you plan to do this later on, make sure you request that your PB leave sufficient empty space on your equipment pad for installing an acid dosing system as well as enough space on your PVC pipes to make any necessary connections.
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Just to be clear, ORP voltage is used as a proxy for free chlorine concentration. In theory, the measured ORP voltage should decrease with decreasing FC. However, in practice, there are so many other variables to your pool water (pH, CYA, TA, etc) that also affect the ORP voltage signal that it can make it difficult to figure out what is really happening. A salt water pool only confounds the problem further by adding another variable to the system, namely salt concentration as measured by a proxy value called TDS (total dissolved solids). Can these things be measured and controlled? Sure. But when your pool water goes out of whack, you'll be the one to debug all these things so keeping it simple up front will make your life a lot easier.
pH probes are similar to ORP probes but are a little less sensitive to all the "noise" generated by the other pool water parameters.
That was the basis of my recommendation to you that you consider only using a a time-based acid dispensing system. Pentair sells the IntelliPH system that many in this forum have successfully installed as DIY projects and I'm sure Hayward has something similar. Using a time-based system is ultimately much easier to understand and debug as all you have to do is adjust the dispensing time up or down to lower or increase your pools pH. Believe me, your pH isn't going to change second by second. pH swings in most well balanced pools happen over days and weeks, a time frame well within your ability to get a handle on, test and control.
And I do believe your dad is/was a very wise man....and one more tip - if you plan to do this later on, make sure you request that your PB leave sufficient empty space on your equipment pad for installing an acid dosing system as well as enough space on your PVC pipes to make any necessary connections.
Sent from my iPhone using Tapatalk