Risks with high alkalinity?

[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.

[Rangeball]

Got my alk down to 115, then had to add 3" of water. Lowered PH to 7, and had kids over again yesterday (not near as many). Today PH was 7.6 and alk was only 130. Dropped PH to 7 again, more kids coming swimming this afternoon, will retest alk and PH tonight.

I should end up with a full pool and a 110-20 alk, which should hold me for awhile.

[Rangeball]

I may have screwed up...

Sunday afternoon I broke my DE filter down for the first time all year. Cleaned it good, fired back up and decided to go ahead and shock the pool, as I haven't since opening for the season months ago. My CYA is around 20ish, so I used enough 6% bleach to get me 12 ppm.

The next day at lunch, I tested TC with my OTO kit. Pure brownish orange, obviously well above the limit of this test. I knew it would be, but I wanted to see what the max level looked like. Next I tested PH and Alk as stated in the above post. PH was 7.6, alk was 130. Added acid to prepare for kids.
Lot's of splashing about.

I just tested TC, PH and Alk. TC is back down to 3, ALK is at 110 but PH, after all the splashing, was 6.8 to below 7.

I'm wondering if the shock level of TC gave me a false high on PH, and I actually lowered it too much. I did use the chlorine neutralizer before testing PH, but only 1 drop as instructed. Could this be the case?

Kids are coming back this afternoon. I plan to test PH again later this evening, and if it hasn't come back up to at least 7.2 by tomorrow will plan to add some mule team 20 for the first time ever.

[waterbear]

I may have screwed up...


I'm wondering if the shock level of TC gave me a false high on PH, and I actually lowered it too much. I did use the chlorine neutralizer before testing PH, but only 1 drop as instructed. Could this be the case?

Yep, never test your pH when the chlorine levels are high. even with chlorine neutalizer you can get a false high reading. If your OTO was brown you were at a VERY high chlorine level!

[Rangeball]

Not pure brown, brownish orange

I haven't had a chance to check PH today. Lot's of splashing went on yesterday. I'll check it at lunch.

[Rangeball]

Got a chance to test at noon.

My PH came up a bit, now at 7-7.2.

With an alk of 110, I suspect it should still increase on it's own with further aeration, no?

Unless told otherwise, I'm inclined to leave it as is and just monitor it daily for awhile.

[Rangeball]

We had two days of many kids splashing about and then about a 1/2" of torrential rain in a 20 minute period. PH is 7.1

I think the verdict is in. I need to bump my PH just a bit. This is the first time ever I've had to.

What is used to increase PH without affecting Alk? I was thinking Borax, but now I'm not so sure.

[chem geek]

I'm wondering if the shock level of TC gave me a false high on PH, and I actually lowered it too much. I did use the chlorine neutralizer before testing PH, but only 1 drop as instructed. Could this be the case?

In addition to the true points about high chlorine levels (>10 ppm) affecting the pH test (it converts phenol red into chlorphenol red which looks dark purple above a pH of around 6.6 so can fool you into thinking you are at dark red alkaline when you are not), a chlorine neutralizer will also usually increase the pH by almost 0.1 per drop).