Effects of adding fill water calculator

[easttn]

I was thinking the other day how a calculator like that would help me figure out where my TA was going to go after adding a few inches of fill water. For informational purposes I would have used it since I knew my TA was going to go up. Input your current test results, fill water test results and gallons of fill. How does that sound for a suggestion?

 

[easttn]

Does anyone know the math formula for calculating such a task? Ive tried to work it out on paper but nothing seems to make sense.

 

[jblizzle]

For most chemicals it is just a ratio. If you replace 25% of the water:
New level = 0.75*pool level + 0.25*fill level

 

[easttn]

Thanks for the reply. I came up with a formula before you replied that looks the same as what you replied with. I made a javascript calculator with this formula:

Total Gallons = Pool Gallons + Fill Gallons

Pool Gallons / Total Gallons = A
A x pool TA ppm = B
Fill Gallons / Total Gallons = C
C x fill TA ppm = D
B + D = Final TA ppm when mixed

Does that look right to you? I am willing to share the calculator with the community here so people will have an idea of what happens when fill water is added to their pool.

 

[jblizzle]

Looks right to me.

 

[svenpup]

To circle back on what jblizzle said in post 3, if you are replacing water, The "Pool Gallons" in you equation is after draining.

 

[easttn]

I have the calculator made. Had to redo the equations since they got deleted somehow. Anyone interested in checking it out for flaws or suggestions?
I need some people to check it out. Im sure I will tinker with it some more. Where would I need to put it?