Risks with high alkalinity?

[chem geek]

TC/FC- 3.0
PH- 7.6
ALK- 170
CYA- 20ish
What conditions would it take for my pool to go much higher than 8-8.2?

Well interestingly the pH of 7.6 with alkalinity of 170 gives the same "somewhat stable" relative outgassing rate as with Tredge -- his was just over 15 and yours is almost 14.

As for what conditions it would take for your pool to keep rising in pH -- it will always rise until it reaches equilibrium, but the rate of rise will keep slowing down. Unfortunately, it is largely a function of the amount of aeration of your pool so yes, having your kids over and splashing will force up the pH faster. This is not something easily predictable -- it's more something you'll have to keep track of and have a "feel" for. I can tell you that with the "calm" conditions you are now seeing, that a pH of 8.0 will outgass CO2 at about one-third the rate as it is doing now at 7.6 pH so the pH will rise about one-third as fast (again, assuming similar aeration conditions). Aeration is also caused by wind. Basically, only a pool cover would give you a stable and relatively predictable system. Even so, it's kind of eerie that I've now seen several cases that all stabilize near this relative "15" number.

On the other hand, there are those in the rising ph levels thread who experience relatively large pH upward movement without abnormal aeration and with outgas numbers below 15 -- but some of them also do not see the slow drop in alkalinity over time so something else other than CO2 outgassing is causing their pH to rise -- we just haven't figured out what it is.

[EDIT]The number "15" means that the amount of dissolved carbon dioxide in the pool is 16 times larger than the equilibrium amount which is where it would eventually end up if it continued to outgas to air -- that's how far out of equilibrium the pool system is (or how "carbonated" it is).[END-EDIT]

Richard