Highest Acceptable Hot Tub pH?

[Methuselah]

Disregarding the drop test comparator's upper limit, if one could monitor pH accurately what would be the highest it is safe for humans and equipment to run at continuously?

I searched "Cheap pH Meter", the first 4 of 10 pages didn't have the word cheap, but lots had "accurate". I wouldn't mind accurate, but cheap comes first since when pH drifts up I'm thinking from what I read here that above 8.0 is nothing to panic about? Anyway, that's why I asked about the cheap meters @ajw22 was checking out and resurrected that thread. I hope that's OK...

 

[ajw22]

You get what you pay for with pH meters in terms of holding calibration, ease of calibration, precision, and probe replacements.

I don’t think spa water can get to a pH that is unhealthy to humans. High pH is alkaline. High pH is damaging to equipment causing scaling.

 

[mgtfp]

I don't think there is a hard cut-off, where the water suddenly turns into poison. But the higher you go, the the risks that something goes wrong. Like:

Scale -> watch CSI
Metal staining
Unpleasant to swimmers

The general opinion is that up to 8.0 is ok, with a stretch up to 8.2. When metals are known to be in the water or when high in CH, I wouldn't go that high.

 

[Methuselah]

Thanks for the input ... apparently when it comes to pH anything other than the industry standard has challenges

I'm OK with that, mostly just curious