Getting Calcium Levels Right

[jmarcum]

I'll throw in my two cents for what it's worth.

From what I was told (by chem geek), your CSI should be between -0.3 and +0.3. I try to shoot for the middle of all the recommendations on that page. For your setup I would probably go with:

FC - 3 or 4
pH - 7.6
TA - 80
CH - 300
CYA - 40


Assuming no SWCG and with a temp of 65 your CSI would be -.11 which the calculator will tell you the water is balanced. If your water ever got up to 100, your CSI wold be +.19 which would still be balanced. Right now with the current numbers you've input, "Corrosion of plaster is likely". If you go the other way and your CSI is +.3 or greater "Scaling is possible".

I played with that calculator quite a bit to figure out what would be best for my spa and for the pool. Seems to be working out pretty well for me.

Figure out what works best for you and then try to hold those numbers.

Hope I didn't over step my boundaries. Good luck!

I don't understand how to change the CSI though. Are you saying if I hit all the all numbers the CSI will just fall in line?

[JimK]

I don't understand how to change the CSI though. Are you saying if I hit all the all numbers the CSI will just fall in line?

CSI is calculated based on the numbers you out in. You can play around with different chem levels and you will see CSI change. For example, try the numbers Toy suggested and see how it affects the CSI number.

[Toybuilder]

CSI is calculated based on the numbers you out in. You can play around with different chem levels and you will see CSI change. For example, try the numbers Toy suggested and see how it affects the CSI number.

What JimK said!

[FormerBromineUser]

Great posts, guys!

Yea, just try inputing different numbers. Like: if I raise my pH, my new CSI is ___. If I raise CH, and raise/lower pH, my CSI is ___. Play with the numbers until something makes sense for your pool.

[FormerBromineUser]

Edit to above: I noticed on your screen shot that you had several variables that you were adjusting. To experiment with CSI, keep your values the same for both current and target. Only change the target on one, maybe two parameters at a time. These are the parameters that matter: pH, TA, CH, CYA, Temp, and includes any Borates and Salt.

[mas985]

The easiest thing to change is PH because it is a one for one change. Increase PH by 0.5 increases CSI by 0.5. TA and CH changes have less impact.

[Toybuilder]

The easiest thing to change is PH because it is a one for one change. Increase PH by 0.5 increases CSI by 0.5. TA and CH changes have less impact.

Well, that's very interesting. Never noticed that before. Learn something new everyday.