ph and Alkilinity

[Shellbird]

So... I'm now helping my friend with her little pool. She has ph so low it doesn't register and 0 alkalinity. What do I raise first or how do I address this?

It's a 3700 gal. pool. I put in 4 lbs of baking soda and some Borax. Was that a good thing?

When I left her house it was still low. Going to check it again today. They got their pump working and aerating over night.

 

[Donldson]

Generally in these situations I recommend adding enough baking soda to bring the TA to 50 ppm. Let that mix for a day and then retest both. This usually brings the pH up enough to be readable and you can make a more educated guess as to what to add next. If she is using pucks to chlorinate you'll eventually want to get the TA up over 100 to avoid this happening again.

Sure hope they haven't been running like this for a while, the pH was likely around 3 and that will cause all sorts of damage to the pool and equipment over time.

 

[mknauss]

You did right. They can continue to add baking soda until they get a TA of 70 then switch to borax to raise pH, if necessary.
Or, you can use washing soda (soda ash) to raise both TA and pH. But be careful, as it raises TA quickly.

 

[Richard320]

You need to pause and ask how it got so acidic.

My guess is that the pool has been fed a steady diet of trichlor pucks, which besides being very acidic, are chock full o'Cyanuric acid. The CYA level is probably astronomical which renders the chlorine useless to sanitize and kill algae.

 

[Shellbird]

Yes, pucks - I'm trying to educate them on why not to use them but they are a couple of old dogs... they haven't had any algae so they think they are good.
Their results:
FC: 7
pH: ?? LOW
TA: 0
CYA: 58

She said she dumped a ton of bleach in the pool last week, saw it getting cloudy.

The bottom of the pool is completely bleached out. Used to have a blue pattern on the bottom, now it's gone. That never happened to my Intex so I'm thinking the low pH is doing that.