Why is Ph climbing?

[chem geek]

The only explanation I can come up with that is consistent with what these guys are saying is that injecting CO2 into the water increases the Carbonate Alkalinity, which is a true statement. However, there is a difference between carbonate alkalinity and Total Alkalinity. The former does not include [OH-] while the latter does. For the pool alkalinity tests, you measure Total Alkalinity, not Carbonate Alkalinity. For practical purposes, the two are very close in a pool (except at high pH), unless there is CYA present (in which case there is the CYA adjustment that can be made).

What can I say? Perhaps you can do an experiment if you've got one of these CO2 injectors. Just be sure to do the experiment in water that doesn't have other things going on (i.e. living things doing photosynthesis and respiration, etc.).

Anyway, I'm off on vacation. Talk to y'all after next week!

Richard

[waterbear]

The only explanation I can come up with that is consistent with what these guys are saying is that injecting CO2 into the water increases the Carbonate Alkalinity, which is a true statement. However, there is a difference between carbonate alkalinity and Total Alkalinity. The former does not include [OH-] while the latter does. For the pool alkalinity tests, you measure Total Alkalinity, not Carbonate Alkalinity. For practical purposes, the two are very close in a pool (except at high pH), unless there is CYA present (in which case there is the CYA adjustment that can be made).

What can I say? Perhaps you can do an experiment if you've got one of these CO2 injectors. Just be sure to do the experiment in water that doesn't have other things going on (i.e. living things doing photosynthesis and respiration, etc.).

Anyway, I'm off on vacation. Talk to y'all after next week!

Richard

I have started a new thead in the China shop to continue this side discussion since it is getting a bit too technical for the general forum.
http://www.poolforum.com/pf2/showthr...9517#post29517