Carbonate Alkalinity, TA, and pH range for new Pebble Tech pool

[mgtfp]

200 is pretty much the lowest salt level right after a fresh fill. 1000 is more realistic for a pool that's been in use for a while, and the default value that PoolMath uses.

When "Track Salt" is not activated, then "Salt" will not show up when recording a data point, and PoolMath will internally use 1000ppm salt to calculate CSI:




But when clicking on "CSI" on the home screen, then fields for Salt (and Borates) will show up. As long as you leave the Salt field untouched, PoolMath will use 1000ppm salt for the CSI calculation:




If you enter "0" then the default will be overridden:




Entering "1000" will give you the same CSI than before entering a value:

 

[TheMauiBeach]

The version I have been using looks like this. It looks like I just have to enter the 1000.

 

[mknauss]

OK -- by online you meant the old web based page.
Yes. The page should auto enter 1000. If not, you need to enter 1000.

 

[mgtfp]

Is the "salt" field for TDS? The pool store samples I had taken in showed mostly TDS values of 800.

TDS is bit of a useless parameter, because it just tells you that there is "stuff" in the water, but not what the actual composition of that stuff is. TDS is always a bit higher than salt.

Many pool calculators use TDS for the CSI calculation, but PoolMath uses "Salt" because it is a more meaningful parameter, testable with a drop test kit, and SWG users keep track of their salt levels anyway.

In the end, a calculator can use either to estimate - together with the other CSI relevant parameters like TA, CH, CYA - which ions are in the pool water. This is needed to add an "ionic strength" correction to the CSI calculation formula. All those ions in the water basically "shield" the calcium ions and carbonate ions (that the CSI is all about) from each other and make the concentrations relevant for the CSI calculation appear a bit lower to them, i.e. water with more ions will be less saturated with calcium carbonate, i.e. the CSI will be lower (or more negative).

 

[TheMauiBeach]

Got it. I just tested a couple of items tonight to see how they changed over the day.
FC 8
TC 8
TA 80 didn't retest tonight
CH 210 didn't retest tonight
Salt 1000 "default"
90F
CSI is -.09

Full sun today, and hot. My FC dropped from 11 at 7am to 8 at 9 pm. The pH rise from 11am to 9pm was from 7.59 to 7.70. That seems pretty good.