Water PH'ing

T

Turbonyg

Active Member
Hey All,

Working on my first grow and trying to figure out water PH'ing. I'm trying to keep this and the next couple grows simple with Auto's and soil using FFOF.

Tap water 7.3ph 355tds
RO water 8.3ph 37tds

Curious as to why the PH on the RO would be higher. I don't have a reason to use RO, I just already have it (I didn't buy it for growing).

What are some preferred methods to organically lower the tap ph.

Thanks.
 
JavaCo

JavaCo

Well-Known Member
Turbonyg said:
Hey All,

Working on my first grow and trying to figure out water PH'ing. I'm trying to keep this and the next couple grows simple with Auto's and soil using FFOF.

Tap water 7.3ph 355tds
RO water 8.3ph 37tds

Curious as to why the PH on the RO would be higher. I don't have a reason to use RO, I just already have it (I didn't buy it for growing).

What are some preferred methods to organically lower the tap ph.

Thanks.
Click to expand...
You can just water the soil FFOF should buffer itself for a couple months at least. But if you really want to PH the water you can use something like citric acid. PH ing of water is mostly done when nutrients are added to the water and take the PH way down because they break the nutrients down with acids making them more soluble to plants and also it makes the product more shelf stable. You are better off measuring the PH of the soil Directly when growing in soil rather then the water. Bad thing is a decent soil PH meter will set you back a couple hundred dollars. Personally I would use the RO water unless I saw a report from the water department of what the 355 tds actually is.
 
OldMedUser

OldMedUser

Well-Known Member
RO water has no real pH of it's own so your pen isn't reading it correctly. 37ppm shouldn't be enough to move the pH either way. It's such a minor amount that a tiny bit of anything slightly acidic like most nutes will drop it below 7.

Add your CalMag or nutes to it then check the pH and adjust if needed.

That's pretty hard tap water so expect issues with long term use of it.

:peace:
 
T

Turbonyg

Active Member
JavaCo said:
Bad thing is a decent soil PH meter will set you back a couple hundred dollars. Personally I would use the RO water unless I saw a report from the water department of what the 355 tds actually is.
Click to expand...
I wondered about soil ph'ing and saw the cheap meter at the store and passed on it being not sure it would be accurate. I haven't been able to find a water report online that has a full list, only had a listing of things they were concern with monitoring. I do know we have a high calcium percent as it spots of the windows and cars bad.


OldMedUser said:
RO water has no real pH of it's own so your pen isn't reading it correctly. 37ppm shouldn't be enough to move the pH either way. It's such a minor amount that a tiny bit of anything slightly acidic like most nutes will drop it below 7.

Add your CalMag or nutes to it then check the pH and adjust if needed.
Click to expand...
I didn't know what to expect from the RO, but figured it would be close to 7 as it wouldn't have hardly anything in it.
I started feeding only CaMg+ this week as all the plants seem to have a Ca issue. I'm not feeding anything else at the moment. They have been in the current soil about 4 weeks now I think and are very small due to other mistakes starting out. They just started showing they are going into flower now, so probably should add nutes for that.


PissingNutes said:
Recalibrate the PH meter often. And like OldMedUser says RO water is pure and shouldn't be used to measure, just clean your probe when it's off.
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Ok, didn't realize it would loose calibration. I calibrated it a couple weeks ago when I got it.
 
gremlinboy14

gremlinboy14

Well-Known Member
FTW I just use bottled water ph is neutral.
A quick Natural and Cheap method to mess with the ph level:
!To lower PH add baking soda
To rise PH add vinegar*!
 
Renfro

Renfro

Well-Known Member
Turbonyg said:
Curious as to why the PH on the RO would be higher.
Click to expand...
You really can't get a good pH reading on RO water, there is nothing to read. A very small amount of buffer added will have a bigger effect since the TDS is low compared to tap. Consider the RO water's PPM as the key. Only worry about it's pH after you add nutes. Otherwise consider it to be 7.0.
 
Renfro

Renfro

Well-Known Member
Also, don't water your plants with straight RO water, it basically tries to pull nutes out of the roots via osmosis. Get some calmag in there, then pH it.
 
OldMedUser

OldMedUser

Well-Known Member
Renfro said:
Also, don't water your plants with straight RO water, it basically tries to pull nutes out of the roots via osmosis
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I don't know about that. I water with straight RO often and all it does is dissolve what nutes are in the media and the plants feed like normal.
 
OldMedUser

OldMedUser

Well-Known Member
Turbonyg said:
Ok, didn't realize it would loose calibration. I calibrated it a couple weeks ago when I got it.
Click to expand...
Whatever you do don't leave the pen in RO water for any length of time or you will ruin the probe. You should have some storage sol'n to keep it in when it's not being used. Just don't test straight RO water at all except for ppm. The ppm pen should be rinsed with RO after use and the cap left off so it can dry. Just the opposite of how to treat the pH pen which should kept moist at all times with the storage sol'n. or even dilute pH 7 calibration sol'n.
 
Renfro

Renfro

Well-Known Member
OldMedUser said:
I don't know about that. I water with straight RO often and all it does is dissolve what nutes are in the media and the plants feed like normal.
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That works well if you have something thats not inert media. So yeah but still better to add calmag because the water is generally the source of these nutes. If in perlite or coco or DWC lol then the RO water will really piss a plant off unless you add some nutes.
 
OldMedUser

OldMedUser

Well-Known Member
Renfro said:
If in perlite or coco or DWC lol then the RO water will really piss a plant off unless you add some nutes.
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As long as the perlite or coco has had nutes before there would be plenty left but for sure you wouldn't want to feed RO water only for any length of time and in hydro like DWC soaking the roots in plain RO will screw things up for sure.

:peace:
 
P

PissingNutes

Active Member
OldMedUser said:
I don't know about that. I water with straight RO often and all it does is dissolve what nutes are in the media and the plants feed like normal.
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This is one question where variables are really at play because it's hard to judge how a treated medium reacts exactly besides reading runoff total PPM. If it's hydronic and even soilless hydro they say consistency and feed every watering.
 
Last edited:
T

Turbonyg

Active Member
Renfro said:
Also, don't water your plants with straight RO water, it basically tries to pull nutes out of the roots via osmosis. Get some calmag in there, then pH it.
Click to expand...

RO water has all of its ions intact, it’s just void of most all minerals and other additives (city water), so you are using almost pure water.

De-Ionized water, the water molecule is missing an Ion and looks for one from anything to grab and complete its chain.

Distilled water should be similar to RO except that it “should” have a TDS of 0.

Rain water starts at 0 TDS, but will pick it up depending on how dirty the run off surface and catch/containment system is.

So all of these sources are basically void of any nutritional value to the plant.
 
Budzbuddha

Budzbuddha

Well-Known Member
My Cali water is close to your readings ... 7.2 320ppm .
FFOF out of bag is 6.3 . I use a pinch ( literally ) of Alaska Ph crystals ( citric acid )
Ph soil 6.5 -6.7 ....
A059CC2F-C16D-4A51-8388-BDCCC99D6A68.jpeg
and life goes on.
 
JavaCo

JavaCo

Well-Known Member
Turbonyg said:
I wondered about soil ph'ing and saw the cheap meter at the store and passed on it being not sure it would be accurate. I haven't been able to find a water report online that has a full list, only had a listing of things they were concern with monitoring. I do know we have a high calcium percent as it spots of the windows and cars bad.
Click to expand...
Those meters can work correctly, but unless you have a really good one that can be calibrated to put next to it, no way to know if it is accurate. A well planned and mixed soil you won't have to worry about cal /mag it will already be in the soil in a uptakeable and organic form for the plants.
 
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