ORP system help needed.

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mknauss said:
With higher pH and TA, your SWCG will shed calcium scale. Be ready for that.
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Got to thinking more about that.
That IC-60 is 2 years old now. I inspected the cell in 2019 and again this year. Still clean as a whistle. No scale at all. Don't get me wrong, I'm not complaining. ;)
Wonder if that is due more to the fact that water is always slightly negative on the CSI scale (usually around -0.30 to -0.50), or the fact that ma injection is about 12" upstream from the cell? Certainly a combination of both I'm sure but I just can't help but wonder, which factor has the biggest impact. 🤔.
And just curious if allowing CSI to go just slightly positive (less than +0.50) would be too detrimental.

I know, "stop overthinking this, myazpool" :p I get it.
Thanks..
r.
 
Maintaining a negative CSI will assist in keeping the cell clean of scale. Not sure about the acid, I would think the contact time would be so short that it would have little effect.
 
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CSI and LSI fundamentally try to calculate the same thing - how over-saturated or under-saturated is the water with respect to the solubility of calcium carbonate. The difference is in how the calculation is done. The Langlier saturation index formula comes from a phenomenological model (statistical or empirical model) of mineral saturation that was developed using data from Midwestern lakes and rivers. It’s an “engineering” approach to determining the saturation of water used in boilers and water delivery systems. It has been heavily modified over the years to add in effects that were not well known at the time when it was first articulated (1920’s & 1930’s). The Calcite Saturation Index is a first-principles model (one derived solely based on the laws of physics and chemistry) that describes the exact thermodynamic equilibrium of calcite saturation in aqueous solutions. CSI incorporates the independent variables of pool water analysis (calcium & carbonate concentrations, temperature, pH, ionic strength, etc) and uses a formula to describe the condition of the water as being either over-saturated, under-saturated, or balanced. It is a more precise model. However, the differences between the two are minor and where exactly scaling or dissolutions starts is a matter of observation and is situational to the local environment of the pool.

One can use either index but TFP prefers that CSI is used as it is the more exact formulation and one can actually use the index number to calculate actual saturation values.

It’s cold enough now in AZ that you can let your pH and TA drift up higher and still jut worry about scaling. If you turn off your SWG and switch to manual chlorine action, then a positive CSI is no big deal. I usually switch to manual chlorination around mid-December abs then I let my pH live up around 7.9 until spring.
 
What is the difference between LSI and CSI? I plugged my numbers in both calculators, and they came out almost exactly the same.
fc - 1.5
ph - 7.8
ta - 70
temp - 55
calc - 340
CYA - 20
tds - 800

CSI = -0.03
LSI = -0.02
 
JoyfulNoise said:
CSI and LSI fundamentally try to calculate the same thing - how over-saturated or under-saturated is the water with respect to the solubility of calcium carbonate. The difference is in how the calculation is done. The Langlier saturation index formula comes from a phenomenological model (statistical or empirical model) of mineral saturation that was developed using data from Midwestern lakes and rivers. It’s an “engineering” approach to determining the saturation of water used in boilers and water delivery systems. It has been heavily modified over the years to add in effects that were not well known at the time when it was first articulated (1920’s & 1930’s). The Calcite Saturation Index is a first-principles model (one derived solely based on the laws of physics and chemistry) that describes the exact thermodynamic equilibrium of calcite saturation in aqueous solutions. CSI incorporates the independent variables of pool water analysis (calcium & carbonate concentrations, temperature, pH, ionic strength, etc) and uses a formula to describe the condition of the water as being either over-saturated, under-saturated, or balanced. It is a more precise model. However, the differences between the two are minor and where exactly scaling or dissolutions starts is a matter of observation and is situational to the local environment of the pool.

One can use either index but TFP prefers that CSI is used as it is the more exact formulation and one can actually use the index number to calculate actual saturation values.

It’s cold enough now in AZ that you can let your pH and TA drift up higher and still jut worry about scaling. If you turn off your SWG and switch to manual chlorine action, then a positive CSI is no big deal. I usually switch to manual chlorination around mid-December abs then I let my pH live up around 7.9 until spring.
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@JoyfulNoise
Matt, I couldn't have asked for a more in-depth and yet (easier to understand), explanation. And the latter is important for me. :p...
Thanks... Now all I need is some of that famous @JoyfulNoise roast that you cooked up yesterday, and my day will be complete.
Thanks again... :thumleft:
r.
 
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And with that, I'm going to allow my pH (and TA), to drift up a tad. Mr. IntelliChlor is just about done until the spring anyway, so a slight bump up in CSI, shouldn't be any big deal until its warm enough to re-engage the SWCG.
r.
 
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jlsesler said:
What is the difference between LSI and CSI? I plugged my numbers in both calculators, and they came out almost exactly the same.
fc - 1.5
ph - 7.8
ta - 70
temp - 55
calc - 340
CYA - 20
tds - 800

CSI = -0.03
LSI = -0.02
Click to expand...

As Matt said, they are fundamentally the same. LSI is also a CSI, and PoolMath's CSI is also just another CSI.

Just played a little with the Orenda app, looks to me like their LSI is very similar to our CSI (certainly different to the LSI as calculated with Chem Geek's spreadsheet, which is the "traditional" LSI that the spreadsheet calculates as well as CSI).

I have the impression that the Orenda app uses basically the same algorithm as PoolMath, but Orenda chose to give their CSI the more traditional, and in the industry more known, name LSI.
 
mgtfp said:
As Matt said, they are fundamentally the same. LSI is also a CSI, and PoolMath's CSI is also just another CSI.

Just played a little with the Orenda app, looks to me like their LSI is very similar to our CSI (certainly different to the LSI as calculated with Chem Geek's spreadsheet, which is the "traditional" LSI that the spreadsheet calculates as well as CSI).

I have the impression that the Orenda app uses basically the same algorithm as PoolMath, but Orenda chose to give their CSI the more traditional, and in the industry more known, name LSI.
Click to expand...
That was my experience as well. Little difference between their "LSI" and my pool math CSI. I might guess that your assumption is correct.
r.
 
MyAZPool said:
Now all I need is some of that famous @JoyfulNoise roast that you cooked up yesterday, and my day will be complete.
Thanks again... :thumleft:
Click to expand...
Just PM him your address and he will send you all the roast you want. I get a delivery once a week. It's great.

[edit]I'm actually not sure that the roast is coming from Matt. It just started showing up once a week. I just assumed it was from him, but maybe not since I never sent him my address. :unsure:[end edit]
 
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