Citric acid as ph down

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B

bluejay

87
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Sounds like this is the safest and will add flavor to the plants...anyone tell me how much they use per gallon and how far are you dropping the number...like 8 down to 6?
 
M

med.botany

104
0
i use a 1/4 tsp/ GAL...check then adjust from there...a 1/4tsp works on my RO but everybody's water is different
 
Oldsog

Oldsog

Supporter
100
43
mix a few table spoons in a bottle with water. slowly add that to your rez OR get your rez to around 7 before you add your nutes, i've found it usually falls into range after you've added your nutes. at least with pure blend pro and house and garden. generally as your TDS goes up your Ph goes down.
 
Mr. Molecule

Mr. Molecule

69
18
It isn't going to add flavor to the plants any more than any other acid would (and they don't add any), but it's a great acid to use as pH down in veg or during flush when you don't want to add any extra mineral salts to the medium.

During flowering, phosphoric acid down is a good choice for the obvious reason.
 
G Star

G Star

46
18
Sorry to bump an old thread, but I have had nothing but problems with ph stability and citric acid, it just seems to break down over night and can't keep up with a standard ph UP product (I use grow more FYI) so my ph ends up closer to 7 rather than 5.8 after 12 hrs... Just my 2cents
 
C

Canvas

20
3
I grow in organic soil, and use Apple Cider Vinegar for ph down, along with Orange Juice, the kind you get from the supermarket, both work a charm.
Pretty sure neither belongs in a supposedly sterile hydro res, but if you are running active microbes in your res these may do well at 1/4 tsp per gallon.

For a sterile res, try Distilled White Vinegar, it's just acetic acid in water.

I will bet that the citric acid breaks down faster than acetic acid, or is taken up by the plants, vinegar is quite stable at ph 6.0, at least while it is still in the jar.
 
homebrew420

homebrew420

2,129
263
We used Citric for a while and noticed the same thing mentioned by Gstar. It does breakdown easily it also promote algae blooms. its Phosphoric now. Works great. Heard the same on the Sulfuric.

Peace
 
Cat Jockey

Cat Jockey

264
28
Sorry to bump an old thread, but I have had nothing but problems with ph stability and citric acid, it just seems to break down over night and can't keep up with a standard ph UP product (I use grow more FYI) so my ph ends up closer to 7 rather than 5.8 after 12 hrs... Just my 2cents

I have, over the years, gradually gone away from using pH up and down. I avoid adjusting the pH of my res at all costs. It is just one more little thing that disrupts the harmony of your res. On top of that, your standard pH adjusters are not good for your roots and precipitate useful nutrients out of your solution. Even though minor, it has a negative effect on the integrity of your solution and even worse, adding pH down to your res one day and then up the next day is a not a good thing to do. What I have done, is to make sure I am using nutrients that are properly adjusted by the nutrient company so that when I mix them, the pH is at a good starting point.

What kind of hydro system are you running?

What kind of nutrients are you running?

What is your starting pH on a fresh res with no adjustment?

What is your target pH range?

Most of the alternate pH adjusting methods (citric acid, vinegar, aspirin, etc.) don't hold the pH for very long, just like you are experiencing and you just have to keep pouring more and more stuff into your res, that ideally, you really don't want to.
 
joehank

joehank

131
28
Cat, are you using RO water? There is an article in one of the latest Maximum Yields magazines about citric acid, either June or July.
 
R

Rasta311

64
8
I find sulfuric acid to be the best at staying on point. Plus it can be made for a few bucks.

Go to the auto parts store and buy battery acid. Should be under $5. Now mix 1 cup of that to 1 gallon of ro water for instant ph down. One container of battery acid should make 5 gallons of ph down.
 
S

singularity

37
8
Same experience as others mentioned here. Citric acid as pH down in DWC = completely unstable. Even while adjusting it I found it was susceptible to mad swings... "bounce". I read it's a source of carbon which feeds bacteria, so that's not good for stability, and that its' also a "Weak" acid, meaning under the best of circumstances its' still going to break down rapidly. pH "slowly drifts up" from 5 to 6 over the course of 12 hours. I have found some plants don't mind that crazy swing, in dwc at least..while some were stunted by it.

Phosphoric Acid is a "medium" acid, and sulfuric acid is a "strong" acid. Therefore phosphoric acid will break down sooner than sulfuric, but no where near as fast as citric.

I could not locate a reasonable size of sulfuric acid in my location. It was 5 gallons of it or nothing and I wasn't about to buy 5 gallons of acid. I was able to pick up a liter of 85% phosphoric, diluted it 10:1, and have used up less than a tenth of that in over a week. Great stuff... ph drift is actually "slow", at around 0.1 per day while dialed in.

I held it so steady for a week that it killed one of my plants.

Initially while I was testing the setup, bubbling plain water and trying to set the pH, the citric acid would actually hold for several days with very little drift. Soon as you introduce anything into it though, like nutrients, that might feed bacteria, and once they're established.... you can forget all about your "organic" pH adjuster. I had such a difficult time of it with that, adjusting the pH twice a day just to half keep on top of that, I gave up on the pH, and wondered why in the hell they even sell a product like that that doesn't work.
 
H

HD wow

9
3
I have, over the years, gradually gone away from using pH up and down. I avoid adjusting the pH of my res at all costs. It is just one more little thing that disrupts the harmony of your res. On top of that, your standard pH adjusters are not good for your roots and precipitate useful nutrients out of your solution. Even though minor, it has a negative effect on the integrity of your solution and even worse, adding pH down to your res one day and then up the next day is a not a good thing to do. What I have done, is to make sure I am using nutrients that are properly adjusted by the nutrient company so that when I mix them, the pH is at a good starting point.

What kind of hydro system are you running?

What kind of nutrients are you running?

What is your starting pH on a fresh res with no adjustment?

What is your target pH range?

Most of the alternate pH adjusting methods (citric acid, vinegar, aspirin, etc.) don't hold the pH for very long, just like you are experiencing and you just have to keep pouring more and more stuff into your res, that ideally, you really don't want to.


humid acid is an excellent ph buffer

natures way .... this is what plants use to buffer the soil from ph variations

attributed to MR Harley Smith

I now us it in my aero set up

we are commercial its amazing the way it works cheap as hell to 1/16 of a tsp per gallon

which when running large ops this is a added bonus

in addition it acts an as amplifier for nutes like kelp

fulvic acid plus kelp ( kelp contains iron) which stimulate chlorophyll which intern = chloroplast increased production = plants ability to harvest more light energy= higher sugar content= bigger buds & more nutritional value for medicine

this is the iron homeostasis theory

we all want the best lights best reflectors etc so it only makes sense to do things to increase ability to use all that light
 
Last edited:
Lorcan

Lorcan

10
3
How often and what dose for kelp (velokelp) if you please?
As you mentioned bout lamps,, is it better to have a v.small reflector, as cool tube, or a bigger one in small space, 60cm x 120 x 72 high.?
Thanks very large
 
P

Psycho gym

10
3
Sorry to bump an old thread, but I have had nothing but problems with ph stability and citric acid, it just seems to break down over night and can't keep up with a standard ph UP product (I use grow more FYI) so my ph ends up closer to 7 rather than 5.8 after 12 hrs... Just my 2cents
a pH of 5.8 is better than a ph of 7
 
P

Psycho gym

10
3
mix a few table spoons in a bottle with water. slowly add that to your rez OR get your rez to around 7 before you add your nutes, i've found it usually falls into range after you've added your nutes. at least with pure blend pro and house and garden. generally as your TDS goes up your Ph goes down.
it's a better idea to test your water and then add your newts let him sit overnight shake it up real good and test it again and den PH
 
H

Holygrail

3
1
Sounds like everyone should read on the citric acid cycle. If there's any bicarbonates in your rez, then citric acid makes carbonic acid which turns into co2. Carbonates may also be found in your soil as ph buffers. Another tool on the belt If you ask me.
 
Aqua Man

Aqua Man

26,480
638
Sounds like everyone should read on the citric acid cycle. If there's any bicarbonates in your rez, then citric acid makes carbonic acid which turns into co2. Carbonates may also be found in your soil as ph buffers. Another tool on the belt If you ask me.
can you explain? and citric acid should not be used in a res. Soil is a different story.
 

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