Citric Acid lowers PPMs

Rurumo

Rurumo

Well-Known Member
Hello all,
I just noticed this and thought it might not be common knowledge...or maybe it is, idk. I've been messing around with my water a lot lately, testing it, testing various PH up/down options, etc. This is the first time I've used this source of water to grow indoors and it's moderately hard...ph around 7.5 and average 300 ppm. I've always used citric acid to lower PH in the past because I typically used organic nutes and I figured it was the safest thing for my microherd, and it's incredibly potent-I used to use a mg scale to measure it out, but today I just tried to eyeball it and if you're only adjusting a gallon of water at a time, you only need the tiniest pinch of it. What I realized was that the amount I used to lower my PH from 7.5 to 6 ended up lowering my PPMs by around 80-100 ppms. That's all- it's very consistent too. I've subsequently verified this phenomenon by way of the internet and lots of science words, but it doesn't seem to be especially common knowledge on the cannabis boards. I thought it might be useful for others struggling with high alkalinity water, since the more common PH down products (phosphoric acid) actually ADD ppms. For the past few weeks I actually thought my TDS pen was super inaccurate because of this, so I have another one in the mail right now-well, mystery solved!

Merry Xmas peeps, I hope Santa stuffed your stocking with citric acid!
 
Last edited:
PadawanWarrior

PadawanWarrior

Well-Known Member
Interesting. I have similar water, and use citric acid occasionally. I don't use it to adjust my pH really though, I let the soil buffer the pH for me. I use it to help flush out excess Ca in my soil.

My thought is that the citric acid is attaching to minerals like Ca and then they precipitate out. So some minerals are falling out of the solution. At least that's what I'm guessing. But I'm not positive.
 
pulpoinspace

pulpoinspace

Well-Known Member
Rurumo said:
Hello all,
I just noticed this and thought it might not be common knowledge...or maybe it is, idk. I've been messing around with my water a lot lately, testing it, testing various PH up/down options, etc. This is the first time I've used this source of water to grow indoors and it's moderately hard...ph around 7.5 and average 300 ppm. I've always used citric acid to lower PH in the past because I typically used organic nutes and I figured it was the safest thing for my microherd, and it's incredibly potent-I used to use a mg scale to measure it out, but today I just tried to eyeball it and if you're only adjusting a gallon of water at a time, you only need the tiniest pinch of it. What I realized was that the amount I used to lower my PH from 7.5 to 6 ended up lowering my PPMs by around 80-100 ppms. That's all- it's very consistent too. I've subsequently verified this phenomenon by way of the interne and lots of science words, but it doesn't seem to be especially common knowledge on the cannabis boards. I thought it might be useful for others struggling with high alkalinity water, since the more common PH down products (phosphoric acid) actually ADD ppms. For the past few weeks I actually thought my TDS pen was super inaccurate because of this, so I have another one in the mail right now-well, mystery solved!

Merry Xmas peeps, I hope Santa stuffed your stocking with citric acid!
Click to expand...
Nice post. Pretty fascinating to think about.

PadawanWarrior said:
So some minerals are falling out of the solution. At least that's what I'm guessing. But I'm not positive.
Click to expand...
Thats what it sounds like huh? Maybe the minerals closest to where the acid hits the water?

Does the same effect occur if you dilute the acid before adding it to the solution?
This is the kind of thread we need more of.
 
2

2TokesTommy

Member
Good info.

My understanding is that this is predominently used to lower the effect of having hard water calcium build up in your medium and messing up your ph - mostly by organic growers. That's why I use citric -based on this reaction with Ca. Some local Promix growers who reuse their medium had given me this advice has our water is fairly hard. Happy to hear they may be right!
 
Wizzlebiz

Wizzlebiz

Well-Known Member
cannabineer said:
I am glad that “sell” was not within my purview
Click to expand...
I quite enjoy it. I teach people how to maximize their earning potential.

In which I make money from.

See regardless if you are teaching college courses or you are teaching sales to people. The end truth is we both are giving people skills to go out into the world and earn good money.

Thats something I can sleep well at night with the knowledge of.
 
PadawanWarrior

PadawanWarrior

Well-Known Member
cannabineer said:
I don’t think there is precipitation. My guess is that citrate dianion is displacing bicarbonate monoanion, which goes away as CO2.

Same cation number, reduced anion number ... lower readable TDS.
Click to expand...
How does the citric acid react with Ca in the soil? I swear it binds with it somehow and lets it get flushed out easier. Or it breaks some bond or something. I heard it was a chealating reaction or something like that.

I took chemistry in college, but I didn't major in it.
 
cannabineer

cannabineer

Ursus marijanus
PadawanWarrior said:
How does the citric acid react with Ca in the soil? I swear it binds with it somehow and lets it get flushed out easier. Or it breaks some bond or something. I heard it was a chealating reaction or something like that.

I took chemistry in college, but I didn't major in it.
Click to expand...
I believe the term that applies is “solubilization”.
Many soils have significant lime content. Citric acid would quickly and effectively mobilize some of that and make it available to the roots.
 
You must log in or register to reply here.
Top