Distilled water question

i guess i should know this but does distilled water have chlorine? like do i need to leave the cap of for 24+ hrs

It doesn’t. Pure distilled is absent everything other than H2O.


how about the ph, ive read its 7 and 5.8…my apera ph meter shows 7.8- i recalibrated it and checked multiple times to make sure it was a correct reading

Distilled has no pH. pH is a function of the electrical charge of particles in the water. There are no particles in distilled, and therefore no pH exists.

pH measurements of distilled water are not valid for this reason.


oh ok ty for shedding some light, so when i add nutes for feeding ill just ph accordingly after? how about when just plain watering with distilled- anything needed at all

Once you add particles (nutes) to distilled water, it is then necessary to correct the pH.

If feeding plain distilled, no adjustment is necessary. The distilled water will take on the pH of the medium to which it is added.


If distilled water isn’t kept in an airtight container, carbon dioxide gas will dissolve in it over time,
forming carbonic acid, & lower the pH.

Best practice is always check the pH of your water & fertilize mixed water.

What Is the pH of Distilled Water? | Sciencing ok have a look at this link it tells you that distilled water has a ph of 7

You might want to reread the last sentence of the first paragraph of that webpage again.

Distilled water, by definition, has no pH.


Im just posting what ive seen on the internet

While the article you posted is factually correct, it is important to not mislead people in the interpretation of what the article says. An open container of distilled will indeed absorb CO2 and synthesize carbonic acid and develop a pH; however, it is no longer considered pure H2O at that point and it therefore no longer meets the definition of pure H2O. Distilled is most often delivered in gallon jugs. When the jug is first opened it has no pH as it has not been exposed to CO2, and that is the form in which most growers will use it. Interpreting the information and suggesting that distilled has a pH is just not accurate and may lead people to become frustrated trying to pH their distilled water or understand inaccurate readings from a pH meter.


i learned this yesterday by doing exactly what you said- trying to ph plain distilled lol

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Hey man i agree with you have a look at this i still have more critical purple auto to trim this is what i have so far

I don’t know how much there is yet

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I will also point out that the instruments we use are only approximations of true PH or TDS. There are different means for accurately measuring same that don’t include EC. For example I had a TDS meter that would not read sugar being mixed in to solution. And I mean a LOT of sugar. Still read under 100 ppm. That said, they are probably the most important tools in the growers’ toolbox.


Pure water is a pH = 7. But pure water is chemically aggressive, will rapidly oxidize most things it comes into contact with, and will not remain pure water for very long.

The TDS is so low it really doesn’t matter.

Pure water from a closed container is absent ions and therefore cannot have a pH. It can indeed be considered neutral, but by definition it has no pH. Distilled will take on the pH of the medium into which it is introduced.


Right, because it has no potential hydrogen or some sh!t like that. To make the argument that it’s ph neutral is fair, and that gets associated with ph of 7. All in context of article like you said.

Bottom line here is you are 100% correct in that meters most of use will not read accurately in pure form. Users of distilled should mix their nutrients and then check/adjust ph.

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All of this could more or less apply to rainwater too. I’m going into my second grow using rainwater and using Jacks so when I water I’m mixing nutes. Just this past weekend I finally stuck my Apera PC-60 into the plain rainwater and was surprised when the Apera gave me a near perfect 6.6 Ph reading. Then I switched over to TDS and it came in at a whopping 14.3 or something in that ridiculously low range. That tells me that it’s nearly as pure as distilled or RO and therefore the Ph reading isn’t reliable.
The neutral Ph is great news for the outside girls as in July and August I’ll be running 2gallons a day through those containers. Sometimes more!

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