pH keeps climbing WTF?

[buddin_904]

feel free to talk very chem-y if need be......im very interested in this answer and in continuing this conversation

please respond with what will happen 2 the pH and WHY....in advance thanks man!

 

[spurr]

ok so then whats the real answer....i enjoyed your post about co2 + water makes carbonic acid yielding a lower pH.....so your saying in my case CO2 must have been bubbled OUT of the water yeilding a higher pH value.....

Yea possibly, the carbonic acid can be dissociated by bacteria and then the bubbling could have released the Co2 back into the air, thus allowing the pH to rise, e.x. if the water alkalinity was too high, e.g. > 100 ppm.

But this is only my thoughts, I haven't read anything about it from academia. It does make sense and could account for what you see.

sorry to keep asking questions but u seem cool...sooo whenever someone bubbles a solution WONT co2 bubble out???

It depends upon the state of Co2, wither it's 'bound' to water or not.

you say pH shouldnt rise if its bubbled....so are you saying pH should drop?????
what happens???????

It depends on a few factors, it could rise, or it could drop, microbes can also play a part in pH via. their exudates. It's hard to say what is going on for sure.

what exactly will happen TO THE PH when you bubble a full spectrum nutrient solution at a current pH of 6.0 and at a constant temp of 75*.......thats what im meaning to ask

There is no one-size-fits-all answer. Ammoniacal N (i.e. ammonium) is called an acidic form of nitrogen, but only because of how the plant uses it, not because of it's effect directly upon water pH. And nitrate N is called a basic form of nitrogen, but only because of how the plant uses it, not because of it's effects directly upon water pH.

If your bubbling ferts I think microbes are the main culprit to pH changes, i.e. aerobic bacteria/archaea to (generally) increase pH. However, water alkalinity also plays a big role, you should find out the alkalinity of your water.

 

[FreezerBoy]

You have that backwards, Co2 + water = "carbonic acid". And carbonic acid reduces pH because it's a weak acid (this is a source of acid rain).

Now we're getting somewhere. Airstones cause CO2 to dissipate. Because CO2 exists in the water as carbonic acid, removing said acid will cause pH to rise.

Nutes are also acid. This is why EC and pH move in opposite directions. Until you can measure EC, reduce food levels to 1/2 the bottles suggestion and see what happens.

 

[buddin_904]

Yea possibly, the carbonic acid can be dissociated by bacteria and then the bubbling could have released the Co2 back into the air, thus allowing the pH to rise, e.x. if the water alkalinity was too high, e.g. > 100 ppm.

But this is only my thoughts, I haven't read anything about it from academia. It does make sense and could account for what you see.


It depends upon the state of Co2, wither it's 'bound' to water or not.


It depends on a few factors, it could rise, or it could drop, microbes can also play a part in pH via. their exudates. It's hard to say what is going on for sure.



There is no one-size-fits-all answer. Ammoniacal N (i.e. ammonium) is called an acidic form of nitrogen, but only because of how the plant uses it, not because of it's effect directly upon water pH. And nitrate N is called a basic form of nitrogen, but only because of how the plant uses it, not because of it's effects directly upon water pH.

If your bubbling ferts I think microbes are the main culprit to pH changes, i.e. aerobic bacteria/archaea to (generally) increase pH. However, water alkalinity also plays a big role, you should find out the alkalinity of your water.

thanks for the response spurr

there are no microorganisms present in this hypothetical question btw.....and hypothetically temperature remains a constant....but you bring up water alkalinity....well mine is high as fuck 8.5-9 from the tap....so yes full of bicarbs and OHs from the start....

but the i dont currently bubble my nutes....i did for like 2-3 days once in the past and noticed the pH would skyrocket to 8-9 after nutes were added and pHed to 6, under a airstone. stopped after this value appeared.....

 

[buddin_904]

Now we're getting somewhere. Airstones cause CO2 to dissipate. Because CO2 exists in the water as carbonic acid, removing said acid will cause pH to rise.

Nutes are also acid. This is why EC and pH move in opposite directions. Until you can measure EC, reduce food levels to 1/2 the bottles suggestion and see what happens.

freezerboy!!! my man....come back and hang out for a second broski....

so i was right in asking does bubbling your nutes cause Co2 to bubble out and thusly raise the pH.....are you saying this is the main culprit in a rising pH when using an airstone??? ex.(in a perfect environment, no microorgs, temp constant)

so to clarify, bubbling doesnt add extra OH- to the solution, it causes Co2 to evaporate, causing a drop in pH? is there extra Os added to the solution though??? my guess is yes and THATS why i thought it raised the pH....is it a factor of both of these??

 

[CatManDoo]

I have a whole mess of different stones from different stores. I had 2 blue ones, but they fell apart after week two plus they didnt diffuse very well.

I have been using GH ph up/down. I know you say it's no big deal to add a little twice a day but I then am really gonna worry when I have to be gone for a few days.
I was told be the hydro store guy that I don't neccessarily need a EC meter if I am on a fast change cycle of 5 to 7 days. After they drink a little, I add pH adjusted water. I've read that most of what they are taking in is water. So if anything, adding more water over the course of a few days should slightly dilute the nute solution .
Thanks SPUR, I was planning on calling the water company tomorrow I like your filter idea, maybe I'll try it.

 

[spurr]

thanks for the response spurr

there are no microorganisms present in this hypothetical question btw.....

No worries, glad to help.

There are always microbes, however, sometimes they in lower numbers if using things that hinder microbes (like H2o2, etc.). I still bet they are affecting pH (at least in part), esp. if you are bubbling ferts for a few days.

and hypothetically temperature remains a constant....but you bring up water alkalinity....well mine is high as fuck 8.5-9 from the tap....so yes full of bicarbs and OHs from the start....

High pH doesn't necessarily mean high alkalinity, but, high alkalinity does mean high pH. If you use public tap water you can call your water authority and ask them the level of alkalinity, by law they need to test it and tell you. Also, ask them the total TDS of water, it could be hard.

good luck

 

[spurr]

so i was right in asking does bubbling your nutes cause Co2 to bubble out and thusly raise the pH.....are you saying this is the main culprit in a rising pH when using an airstone??? ex.(in a perfect environment, no microorgs, temp constant)

so to clarify, bubbling doesnt add extra OH- to the solution, it causes Co2 to evaporate, causing a drop in pH? is there extra Os added to the solution though??? my guess is yes and THATS why i thought it raised the pH....is it a factor of both of these??

If Co2 was removed from water, after dissociation of carbonic acid, the water pH should increase, not decrease.

Until we see academic info on this topic it's only assumptions at this point, unless Freezerboy has read academic lit about Co2 off-gassing. The reason is, off-gassing of Co2 should not make pH jump up to 9. Carbonic acid is a weak acid, and water can only hold so much Co2 as carbonic acid, so it doesn't drop pH too greatly...

I bet it's due to these reasons:

1. off-gassing of Co2
2. microbial exudates (esp. bacteria)
3. water alkalinity

When I first mentioned the off-gassing of Co2 I was expressing my opinion, not what I know to be fact.

 

[spurr]

Thanks SPUR, I was planning on calling the water company tomorrow I like your filter idea, maybe I'll try it.

No prob. The filter trick comes from aquarium keepers, and it works well. If you filter with plain s.peat it will not only reduce the alkalinity, but also the hardness of water because hardness is comprised (mostly) of alkalinity ions (e.g. Ca and Mg, etc.).

Good luck

 

[CatManDoo]

Chemistry wasn't my forte but I like your off-gassing theory. Maybe when it's aerating, it speeds the process. I am, after-all bubbling air from the grow room, do you think that has a part?
totally different topic, but has anyone ever tried bubbling supplemented air gas into a DWC?

Ya..Off-gassing

 

[FreezerBoy]

Until we see academic info on this topic it's only assumptions at this point, unless Freezerboy has read academic lit about Co2 off-gassing.

I'm no chemist nor do I play one on TV. The addition of O2 causing the dissipation of CO2 is just something I read... somewhere. However, remove acid-raise pH is carved in stone.

Our collective trouble here is, a little knowledge can be dangerous and CatMan has given us just enough info to blow us all to kingdom come.

What was the starting pH/EC of the water? Well water/city water?What did he use to lower pH (avoid vinegar or lemon juice as either lasts for a few hours. pH down is hundreds of times cheaper and lasts for weeks) What are his feed levels, ie EC. Did he nute first and adjust pH last or vice versa?

Cat, we're not asking for fingerprints or your address but, some things we HAVE to know before we have a prayer of helping.

 

[erwingruber]

Hello icmagers ,
So here we are i am writing here before i catch up all of the thread but i counter this issue too and i still live with it.
I make a post yelling for help about my ph updrifts and i try different ways to manage it.
https://www.icmag.com/ic/showthread.php?t=191537

Finaly i learn to live with it and every day i add 2 - 3 ml GH's ph down to fix my updrifting ph.
In 24 hours time my ph updrifts from 5,3 to 5,8.
My ppm's falling if they are weak , stay stable , or even rise but
my ph looks moving without taking in mind ppm's movement.

I live with it cause i cannot fight it.

For information only , i grow 4 plants in 60 liters (16 gallons)
of R/O water with GH's nutes i use a couple of different ratio's
now i am using Lucas formula cause i am in the third week of flowering but ph keep updrifting.
My res is oxygenetad with 4 blue airstones and 20w of airpumps.
and my plants look happy.

I will catch up the thread and keep an eye here cause i would like some day to stop playing with my ph

 

[highonmt]

If Co2 was removed from water, after dissociation of carbonic acid, the water pH should increase, not decrease.

Until we see academic info on this topic it's only assumptions at this point, unless Freezerboy has read academic lit about Co2 off-gassing. The reason is, off-gassing of Co2 should not make pH jump up to 9. Carbonic acid is a weak acid, and water can only hold so much Co2 as carbonic acid, so it doesn't drop pH too greatly...

I bet it's due to these reasons:

1. off-gassing of Co2
2. microbial exudates (esp. bacteria)
3. water alkalinity

When I first mentioned the off-gassing of Co2 I was expressing my opinion, not what I know to be fact.

The process should also reach an equilibrium point rapidly as the total dissolved o2 is quite low. Remember we are not bubbling pure o2 we are also bubbling co2 and n2. The effect of reducing carbonic acid levels would be small and short term. The reason for the continued drop in pH is the salt balance in your solution. You have high salinity which is buffered to 8-9. Every time your plants take up acidic nutrient salts your ph rises. And ditch the blue air stones the ones I had fuked my ph up constantly even though they are supposedly "inert". You can do an easy experiment by mixing your nutrient solution and bubbling water with an open airline...no stone, see what happens...let us know.

HM

 

[Scrogerman]

lmao, bro dam your getting told "some" cods'wallop, stand by!(you must be really confused"!!!)

Right, if your doing DWC or hydro, you want your PH to drift up slowly, this is a good thing & a sign of a healthy system.(morethat 0.5 PH up in 12 hours signals your solution is too weak, This is NOT a Bad thing unless you are seeing deficiencys!)

Hard water has a better buffering capacity than soft(also a good thing-as long as it aint silly hard).
If you have no Lime-Scale around taps & shower heads Kettles etc your Ok & its not too hard * prolly soft.(softer water 'usually' has a PH in the Mid 7's range approx, but can be higher or lower.

If your PH is shooting up more than 0.5 in 12 hours, you prolly need to increase your feed a bit.
If after say 3 days your PH is still drifting more than 0.5 in 12 hours im certain you need to increase your feed strength.

Right, this is how to do DWC without an EC meter. your OK as long as you have a PH meter.

After Res Change day, Chart PH for 3 days, keep adjusting daily back down to where you want it to be(ie-PH Down). if its still drifting/sweeping up after 3 days(with add-backs/top-ups-1/8th strength) then this is a sure sign that your feed strength (EC) needs increasing.

You need to work out the full strength for that pacific nute line!(harder to do with GH line btw).

With the Canna line(for 1) its simple, the full strength is listed on the bottle at 40mls per 10 litres.
split this number up into 1/8th's or 16ths, take your pick.

Your starting strength will depend on stage of growth of course, but say your in wk 2 of veg your gonna be on 1/4-1/3rd strength.

What you need to do is increase the solution (EC) in 1/8th's or 1/16th's & keep charting PH daily. You will notice after a while that your PH settles where you want it tobe & the upward drift will be alot less & drift less frequently. You want upward drifts of 0.2 - 0.3 daily or within a few days anyway. Once you see your PH settle this way, you know your EC is somewhere near where your plants want it to be.

Im not very good at explaining things but if you think of things like this, your barking up the right tree. if you were using Canna this info would be easy for you to understand.

I really hope this helps ya man, dont give up on Hydro. Soil & organic growing is harder & there is much more to it imo!

My point is you can chart & pilot your DWC Bucket with just a PH meter. Remember Upward PH drift is a possible signal that your plants want more food, this is a sign of a healthy system. overfert & your PH will drift the other way, then you'll know youve added too much & need to add water back to weaken your solution off!

Every Change out day(weekly etc) just up the strength by 1/8th & see where your PH goes(after 3 days) from there! try keeping your add-backs to 1/8th too.

This way is how i was taught years ago & its worked for me ever since. keep it simple!

Less is More! Out of interest what is the PH of your Tap?

Best of Luck to you Bro!

Peace............Scroger!

BTW, ive been using the Blue Airstones for years & years, they are Fine man believe me!

(Why do i think this is in the wrong thread? cant work it out! lol)

 

[spurr]

The process should also reach an equilibrium point rapidly as the total dissolved o2 is quite low. Remember we are not bubbling pure o2 we are also bubbling co2 and n2. The effect of reducing carbonic acid levels would be small and short term. The reason for the continued drop in pH is the salt balance in your solution. You have high salinity which is buffered to 8-9. Every time your plants take up acidic nutrient salts your ph rises.

Good points about Co2, that is why I doubt bubbling off Co2 is the main reason for pH clime. I still think ti's due to water alkalinity (mostly) and bacteria (secondly).

When plants take up "acidic" nitrogen, i.e. ammoniacal N (like ammonium), the roots release H+ protons, thus dropping pH, not increasing it. And not all ions are acidic, when roots take up nitrate N the roots release bicarbonates, increasing pH.

Also, as I mentioned on page 2, roots exude many acidic substances, such as citric acid, etc. Those acids drop pH. The factors of pH isn't as simple as EC.

Ammoniacal N isn't called acidic because of it's direct effect upon water pH. Nor is nitrate N called a basic because of it's direct effect upon water pH. Those forms of N are termed acidic and base only because of the acid or basic nature of the ions the roots exude after/during taking up said ions.

No all ions, when put into water, will drop water pH. Many do, but not all. And the two main forms of N found in fertilizers affect pH in a round-about way, vis-a-vis the ion exudates of roots.

 

[Scrogerman]

All you lads are confusing the OP, he needs an easy wasy to grasp the basics then go from there with the science!

I cant think of an easier way to pilot the grow than the way ive explained! without the use of an EC meter!

remember to write all your Numbers & Observations down, Take Notes, it'll help!

G'Luck bro!

 

[erwingruber]

i am a newb of course but reading around here i learn to manage my ppm's by looking
@ their movement in the solution.


For example :

I start my ppm's @ 1100(.7) and without toping off water i see
my ppm's fall to 1050(.7) in 24 hours time this tells me that my girls need more nutes
(when ppm's falling , ph rising is the normal movement)

I start my ppm's @ 1280(.7) and without toping off water i see
my ppm's rise to 1310(.7) in 24 hours time this tells me that my girls need less nutes
(when ppm's rising , ph falling is the normal movement)


I start my ppm's @ 1200(.7) and without toping off water i see
my ppm's steady to 1200(.7) in 24 hours time this tels me that my girls is balanced
and drinking the same amount of water and nutes
(when ppm's steady , ph must be steady but ..... we like a little bit of ph movement)


In my case i counter all three cases of ppm's movements but my ph ALWAYS updrifting
0,5 point in 24 hours time when other growers keep their ph stable for 2 or 3 days
or with drifts of 0,1-0,2 a day.

I would like to bring my ppm's even higher to try out my ph and see if it will be stabilize
but i am afraid to do this cause my girls look 100% healthy and maybe i must raise my ph over
1540(.7) - EC @ 2,2 and if my girls don't like it i will be sorry.
I didn\t even finish my first hydro round so i learn enough for now , next round
i will fight my ph again with even higher ppm's

note : i use R/O water

 

[Scrogerman]

This may help, Great Thread by BigToke! Basic Water Chemistry, i sugest you bookmark, i must of read it over a 100 times & counting!

https://www.icmag.com/ic/showthread.php?t=23357

 

[spurr]

Hard water has a better buffering capacity than soft(also a good thing-as long as it aint silly hard).

Hard water isn't what buffers pH, water alkalinity is what buffers pH. And water alkalinity makes up a majority of the TDS that is hard water. However, hard water is usually considered to be > 200-250 ppm, but high alkalinity is > 80-100 ppm.

Hard water and water alkalinity are not the same thing, nor do they have the same effect upon water pH, or pH of media (i.e. rhizosphere and "soil solution"; the thin layer of water surrounding media particles).

If you have no Lime-Scale around taps & shower heads Kettles etc your Ok & its not too hard * prolly soft.(softer water 'usually' has a PH in the Mid 7's range approx, but can be higher or lower.

That is untrue. And it's not the hardness that effects pH per say, it's the alkalinity. Soft water doesn't have a pH of ~7, soft water simply means < 200 ppm. That's it. However, water with alkalinity of ~20 to ~80 ppm will have a pH of ~7. And water with high alkalinity, ex. > 100 ppm, often has pH over 7.

High water pH doesn't necessarily mean high alkalinity, but high alkalinity does mean high pH.

If your PH is shooting up more than 0.5 in 12 hours, you prolly need to increase your feed a bit.
If after say 3 days your PH is still drifting more than 0.5 in 12 hours im certain you need to increase your feed strength.

If pH is increasing that much he/she needs to reduce the alkalinity, not feed more, that's the culprit most of the time. Trying to continually reduce pH (via. some fert ions as EC that drops pH, or adding pH down) is only a band-aid to the problem; also, too high of an EC is bad, so it's not a good fix. To fix the problem filtering through plain s.peat to reduce alkalinity is the way to go. If alkalinity is very high, then mixing tap with RO (ex. 50% tap and 50% RO) might be needed to keep water alkalinity < 100 ppm.

 

[erwingruber]

i read it once some months ago !!!
99 more left

R u telling me that i am wrong with what i am doing ?