Hi, I'd like to put the CSI formula into excel. Does anyone have it? Is there a spreadsheet available?
CSI Excel formula?
- Thread starter tomfrh
- Start date
- Jun 24, 2021
- 7,511
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
You will need to enable macros.
@stinsontx also has a pool tracking spreadsheet he will send you if you send him a pm...
@stinsontx also has a pool tracking spreadsheet he will send you if you send him a pm...
- Jun 24, 2021
- 7,511
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
Thanks. It works now. Interestingly I'm getting slightly different answers compared to the poolmath website?
- Jun 24, 2021
- 7,511
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
Yeah, you probably need to view that spreadsheet in context to the time...there have been multiple refinements that have led to the current poolmath CSI. Not likely something TFP's gonna cough up...
For some more context/history, you can do more reading here:
CSI and LSI - Further Reading
www.troublefreepool.com
IIRC the spreadsheet from stinsontx was more closely aligned to poolmath and he worked it out. You might ping him for the spreadsheet.
We are in the deep end, but the best advice is to use pool math...PoolMath
Does the APP give the same answers as this page:
PoolMath
Discover the calculator behind the perfect pool, PoolMath. Dealing with pools has allowed TFP to become the original authors of the best calculator on the net.
www.troublefreepool.com
- Jun 24, 2021
- 7,511
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
- May 3, 2014
- 58,551
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
As long as you enter the assumptions for Borate and Salt the same in each calculation.
- May 23, 2015
- 24,450
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Richard’s excel spreadsheet uses different underlying calculations than the app. His spreadsheet utilizes iterative solvers to obtain a more accurate pH calculation whereas those kinds of mathematical operations are not easily implemented using web programming (HTML/Java) or app programming. So while PoolMath and his spreadsheet are close, they are not exact. If you really want super accurate pH calculations, use Richard’s pool equations spreadsheet. If you want simplified daily tracking and calculations, use PoolMath.
- Mar 5, 2020
- 3,077
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
At the bottom of Richard's sheet is an explanation of how the CSI formula has been derived that is behind PM's calculation.
But the formula itself is not being used in the spreadsheet as Matt already pointed out, carbonate and calcium ion concentrations, and ion concentrations required for ionic strength corrections (which apply to the complete set of equilibrium equations to be solved), are taken from the results of the equilibrium calculations in the spreadsheet. But even there, he had to make assumptions and for example pick a model to be used for ionic strength corrections. It is not a real "simulation" using sophisticated and expensive chemical simulators. Which makes his sheet even more remarkable, to put all of this into excel, and not lose track is quite an achievement.
There are a number of assumptions behind PM's formula to derive the required ion concentrations by means of simple formulas from the parameters accessible to domestic water testing, which Richard explains at the bottom of his sheet.
The more thorough calculation in his spreadsheet shows that the PM formula provides a good approximation. But it is an approximation, there is no other way for a calculation with a simple formula.
But the formula itself is not being used in the spreadsheet as Matt already pointed out, carbonate and calcium ion concentrations, and ion concentrations required for ionic strength corrections (which apply to the complete set of equilibrium equations to be solved), are taken from the results of the equilibrium calculations in the spreadsheet. But even there, he had to make assumptions and for example pick a model to be used for ionic strength corrections. It is not a real "simulation" using sophisticated and expensive chemical simulators. Which makes his sheet even more remarkable, to put all of this into excel, and not lose track is quite an achievement.
There are a number of assumptions behind PM's formula to derive the required ion concentrations by means of simple formulas from the parameters accessible to domestic water testing, which Richard explains at the bottom of his sheet.
The more thorough calculation in his spreadsheet shows that the PM formula provides a good approximation. But it is an approximation, there is no other way for a calculation with a simple formula.
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