Is Borax same as baking soda?

[chem geek]

Carl,

In theory, Cal-Hypo should be no different than bleach or chlorinating liquid in terms of pH. It will rise when added, but then the using up of chlorine will make the pH fall back down again. The only difference should be that instead of having sodium chloride salt after the chlorine gets used up, you end up with calcium chloride salt so the calcium hardness (CH) is increased.

There is a very minor effect on pH from the difference in calcium levels, but is not measurable. There is also extra base added to the Cal-Hypo just as there is for bleach and chlorinating liquid, but the amount is very small and again the effect on pH should be negligible. A rise of 0.1 in pH might be seen after using enough Cal-Hypo to cumulatively add 35 ppm FC (that is then used up). By comparison, it takes enough bleach or chlorinating liquid to cumulatively add about 65 ppm FC (that is then used up) to get that same rise of 0.1 in pH. Again, this is based on my theoretical calculations. If you consistently see something different, then that's something to investigate.

Richard