Risks with high alkalinity?

[Tredge]

Just found out last night that we're having another kid fest Thursday night. Aeration x 100

I plan to lower my PH to around 7 pre party and let them have at it. I'll test the next morning to see where things leveled out.

Aeration X100 means a much faster rise in PH. I'd consider adding Acid mid-party to maintain the PH at ~7. Put those kids to work!

[Rangeball]

Aeration X100 means a much faster rise in PH. I'd consider adding Acid mid-party to maintain the PH at ~7. Put those kids to work!

From Jen's post above-

What I have found is that vigorously aerating it seems I evaporate more water with out rising the ph faster.

I'm confused. Which one is right?

[chem geek]

I'm confused. Which one is right?

From a technical point of view, more aeration means more outgassing of CO2 which means more of a rise in pH. However, there may be a point of diminishing returns and that may be what Jen saw -- that vigourous aeration caused more evaporation but not a noticeable increase in pH. She wasn't saying that aeration did not cause a rise in pH, but rather that extra vigorous aeration didn't seem to make the pH rise much faster but did increase the evaporation rate quite a bit. She found that a good tradeoff was made by doing some aeration that was less vigorous.

The processes that determine the rate of outgassing and evaporation are very complicated. Both depend on the surface area of the air-to-water boundary (including that boundary in droplets) but the specifics of the rates may be quite different. Nevertheless, if certain droplets were to completely evaporate, then you would lose both the water and the carbonate in that water into the air leaving only some salt (like sea spray) to eventually fall back to the ground or get whisked away by wind.

So I don't have an explanation for Jen's observation of an increase in evaporation without an increase in pH. I could imagine that there is a small increase in pH but that the rate of evaporation increases much more so that it appears that it dominates what's going on. The evaporation process may have a non-linear and more rapid runaway effect compared to the CO2 outgassing, but that's just a wild guess on my part.

Richard

[Rangeball]

Ok.

I plan to add the acid and drop the PH as low as possible tomorrow morning so the pool will be ready for them swimming 10 hours later. However, they are now calling for scattered thunderstorms, but I guess I'll still be ok if it rains and we call the kids off because I've noticed rain is one heck of an aerator also

[KurtV]

Ok.

I plan to add the acid and drop the PH as low as possible tomorrow morning so the pool will be ready for them swimming 10 hours later. However, they are now calling for scattered thunderstorms, but I guess I'll still be ok if it rains and we call the kids off because I've noticed rain is one heck of an aerator also

And beyond that, the pH of normal rain is something like 4.5 to 5.5 (and even lower for "acid rain").

[Rangeball]

There's that too

I dropped PH to 7 last night after work. Didn't check alk because I'm running low on test solution and I know I had room to go. We got rain overnight, PH at lunch was 7.2 (again didn't test alk yet) so I dropped it back to 7.0. We are either having many kids or rain tonight .

Will check PH again tommorrow morning and report back. I'd love to get alk down and hold PH around 7.4-6 without it creeping up. Evaporation losses have really slowed down the past week, so maybe I can get away with not having to add 2-3" every week.

[Rangeball]

Wasn't sure if we'd have rain or kids last night. We had both

Rained steady for about an hour before everyone showed up. Was sprinkling with clear sky behind it when the party started. PH was 7.

My daughter dove in first. Her dive trail produced a profusion of CO2 bubbles that lasted several seconds after she got out. It was amazing.

The kids proceeded to pound and thrash the pool for all it's worth over the next 3 hours. I noticed the CO2 bubbles less and less as the evening wore on.

After the party, I added bleach and let the pool circulate over night.

I just tested the water at lunch. PH is 7.6, alk is between 120-30. I added the 130 drop before I let the 120 drop do everything it could, and I'm pretty sure if I'd given it time 120 would have done it. So I'll say 125

This is the lowest my alk has been all year long. I plan to go ahead and lower it again because I lost about 1" of water to splash out, and I'm going to have to add more water as the heat wave is returning and evaporation loss will most likely kick back into high gear. Might as well get it as low as I can before I have to add more high alk water to make my job easier later.