concrete deck poured - pH sky high

[planker88]

We had our concrete deck poured friday, it is cantilever and a lot of concrete and pebbles went into the water. After two days of cleaning it looks nice BUT water test showed sky high pH. I was reluctant to add acid right away since the deck company comes back Thursday to acid wash the concrete - its exposed aggregate.

Is it normal for pH to go this high after decking is poured?

I expect a ton of muriatic acid to go into the pool and drop my pH. Is it safe to wait 2 more days or should I drop pH tonight to the recommended range? My concern is that after the acid wash the pH will plummet and I'll be adding soda ash for pH up again.

I feel like I am on the pool yo-yo string going up and down with the chemicals and balance levels through this build process.

Here are this mornings levels:

PH >8
TA 120
CH 110
FC 5.8
CC 0.2
CYA 60

Thank you for reading

 

[Bama Rambler]

I'd probably go ahead and lower it to the high 7's at least. You don't look like you're in the scaling range even in the 8's, but since you don't really know how much above 8 you really are, you would be well advised to lower it some.

 

[planker88]

Thank you - I added 5 lbs dry acid with little effect on pH. I added 2 qts MA and it dropped the acid demand drops from 11 to 5 with my Taylor test kit.

Chlorine demand seems high - I need to add 2 gallons of walmart 8 pct bleach daily to keep FC over 3.

We have 5 ppl swimming for 4 hrs a day, the pool sits in direct sun all day, water temp is 84, CYA is 60, TA 120.

CC is 0.2

 

[jblizzle]

You are right, that FC demand does seem a little high (5.7ppm / day) ... tell everyone to stop peeing in the pool

You can Perform the Overnight Chlorine Loss Test to see if there is something in the water consuming extra FC. Just maybe raise the FC up to 10ppm and then do the OCLT.