This season I’ve been using RO water from a local store. The pH consistently comes out 8.0+ out of the jug. Is that normal?

RO water has no pH. pH is a measure of charged ions in water. RO water has no ions present and therefore it cannot have a pH. The measurement is invalid until you add dissolved solids to the water. Only then can it have a pH.

If the water is truly reverse osmosis then the pH will creep down as carbon dioxide is absorbed into it. But it has so little parts per million of anything in it you can ignore it. Most of us don’t even bother to check it as no pH meters can give you a true measure of RO water unless you pay a thous…

[image] Spiney_norman: carbon dioxide Great point. As CO2 is absorbed into RO or distilled, it is converted to carbonic acid in the water. Once PPM reaches 100 or so, then a pH measurement is possible.

Thanks for the response. If I’m getting a pH reading is it just a false reading? I ph balance water when I use nutrients, but I have used the water untreated and I’ve had a problem with stunted plants this season.

[image] Darth: is it just a false reading Yes, In anything below 100 PPMs the reading is suspect. My RO is around 5 to 10 PPMs and my meter bounces all over if I try to check pH. Why doesn't my pH Sensor read pH 7 in distilled or deionized water? -... pH electrodes will NOT give…

Thank you for taking time for the comments. I’m going to try a different water source and see if I get similar results.

Just FYI and kinda useless information. But I’m pretty involved with planted FW aquariums and the max CO2 for non injected water (exposed to atmosphere) is between 2 and 4ppm CO2.

I checked my tap water with a test stick -total hardness ppm= 1-100 ppm range -pH=6.8 -chlorine, total=0.25ppm Would that be safe to use without adjustments?

RO water pH question

Nutrients Watering

Docnraq August 15, 2022, 10:08pm 10

Add calmag to your RO to get it up to 250-300 ppm. It then becomes PH stable and can be used to adjust your soil. PH unstable water will become adjusted by the soil instead.

New grower, indoors, yellowing leaves

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RO water pH question

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