Pebblesheen Acceptable Startup Range & CSI

[Jerz]

We finally filled the pool a week ago and I've been trying to keep my pool within the ranges recommended by PTI (pebble technology international) and have felt good with it using the ColorQ2x Pro until I started digging into the Langelier Saturation Index (it finally dawned on me that it's the same as CSI). I've been using pool math daily to get everything in the ranges below until this morning when I calculated the CSI using values in the middle of the ranges in the chart below. If I enter 7.2 pH, 80 TA, 200 CH, 50 CYA and a 52 degree water temp I get a CSI value of -.88... so question is how do I stay in the ranges below AND satisfy the LSI range?

 

[Jerz]

My current readings are:
pH 7.6
TA 83
CH 212
CYA 21
Water Temp 52
CSI Value -.40

If the pH were 7.7 instead of the 7.6 the CSI value would be -.30 so I don't see how I could be in PTI's balance and still keep the LSI between -0.3 and +0.3

 

[mknauss]

At the low pool water temperature, the CSI will be less.
Let the pH rise to adjust.

FYI = the ColorQ test kit is not accurate for CH and many times TA or CYA. It is OK for low FC and pH. Get a proper test kit to measure your pool water chemistry.

 

[Jerz]

At the low pool water temperature, the CSI will be less.
Let the pH rise to adjust.

FYI = the ColorQ test kit is not accurate for CH and many times TA or CYA. It is OK for low FC and pH. Get a proper test kit to measure your pool water chemistry.

Ahh... the TEMPERATURE is the reason. Thanks! I changed everything in the pool math calculator except for the temperature.

I'll also get one of the kits mentioned here to see for myself. I saw some older posts mentioning that the ColorQ wasn't as accurate but thought that surely if there was an issue Lamotte would have corrected it by now. I just like the convenience of it syncing to my phone and the ability to quickly email the results with the waterlink software.

Thanks again...

 

[mknauss]

Use the ColorQ for whatever reason you email the results. It is just that the CH is not accurate. Better to use a consistent drop test kit for real world pool water chemistry.