What is the SWG Run Time Calculator?

A tool that is designed to answer the common question of "how long should I run my pump/SWG". It calculates the run time of your SWG and Pump based on your pool size, the output of your SWG and your daily FC PPM loss. It is designed as a starting point, not the final answer.

UPDATE 8/25/2016:I have completed a number of updates and integrated a suggestion from BestJoeyEver to be able to calculate the SWG % based on the desired pump run time. Here is a quick summary of the updates:

- Added change log
- Changed table to increment by 5% vs 10%
- Added calculation for SWG% based on desired pump run time
- Added basic instructions

Before starting your SWG, it is recommended to use Pool Math and bleach to get your FC to at least the target level. A few FC higher would be better until you dial in your SWG and you know that it is able to replace the 24 Hr FC Demand. The idea is to keep your pool from going below the minimum while you dial in the % and run time.

DOWNLOAD HERE

----ORIGINAL POST-----

Ok, so I am somewhat new and I have read over and over that it is just trial and error but I am still trying to get my SWG % and pump run time figured out. The trouble is that with every 1 hour of additional time or X % change, I don't really have any idea how much more chlorine that will produce in PPM for my pool.

So with known variables and possibly a few assumptions, could a formula be determined?

The goal of the formula would be to determine how long to run the SWG at 100% to get a certain output of PPM.

The variables that we know:

-X PPM loss per day (this would have to come from testing)

-Output of SWG (for example: "Pentair IC40.... will produce approximately 0.45 Kg of free available chlorine per 24 hour period"

-Pump run time

-Pool Gallons

-CYA

Has anyone tried to come up with a formula? What am I missing? On the surface, it seems that it should be possible.

UPDATE:

For those of you that want to try to thebetaversion of a calculator to determine SWG/Pump run time, below is a link to a Excel spreadsheet. Your feedback is welcome. It is designed to be a starting point, not the final answer.

UPDATE 7/20/2016: Added a new SWG Run Time Chart to quickly see various run time values at multiple % output and multiple FC demands.

Basic instructions:

1. Enter Pool Size in gallons

2. Enter your Average 24 hr FC (free chlorine) demand. (this value will likely be between 1 and 4)

3. Enter the amount of FC that your SWG creates in a 24 hour period. If you don't know, consult your instructions/documentation or click the link.

4. Enter percentage output that your SWG is set to. Suggest to start at 100%, then you can change the value to see the change in the run time.

Before starting your SWG, it is recommended to use Pool Math and bleach to get your FC to at least the target level. Higher would be better until you dial in your SWG and you know that it is able to replace the 24 Hr FC Demand. The idea is to keep your pool from going below the minumum while you dial in the % and run time. Pooldv's post #8 has good info on this. Also recommend the the following link: Pool School - Water Balance for SWGs

Your feedback is welcome. Just post to this thread.