My well water tests at 8. I dropped the ph down to 6. Within hours with the air on, the ph was rising. I added 1/2 strength AN nutrients after getting it “in the zone”. It will rise all the way to 8.5-8.7 within a day. I got some Gold Blue ph down and used it to drop the ph (I have a gallon of regular ph down on order). It climbs back quickly with the air on, but if I turn the air off, it climbs much more slowly. It has stunted (if not killed) 2 of the plants and seems to have stunted the others as well. I bought an RO Buddie and am ROing a 55 gallon drum of water. When I test the RO water, the ph is still 8.0 after the RO but the PPM drops from 450ish down to 20ish. Any thoughts/recommendations?. TIA
 
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Realized that I didn't put anything about the medium. I'm using Hydrocrunch (hydroton).
Welcome to the Farm!!!

A few questions for ya!

Have you calibrated your PH tester (4.0 & 7.0 minimum)?
What is the ph of your tap water?
City or well water? ... D'oh just saw that you specifically said "well water"
What is the ph of your fresh RO water?
Did you wash your medium before using it?
What nutes & additives have you added?
How much?
Running a O2 generator?
Chilled or not? (personal curiosity)?

I am sure others will have more questions, but these will get the party started :cool:
 
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Are you in dwc or flood/drip? No reason to use air unless you are in dwc of some sorts or adding a bunch of organic shit.
 
Welcome to the Farm!!!

A few questions for ya!

Have you calibrated your PH tester (4.0 & 7.0 minimum)?
What is the ph of your tap water?
City or well water? ... D'oh just saw that you specifically said "well water"
What is the ph of your fresh RO water?
Did you wash your medium before using it?
What nutes & additives have you added?
How much?
Running a O2 generator?
Chilled or not? (personal curiosity)?

I am sure others will have more questions, but these will get the party started :cool:
I have calibrated my PH tester.
PH of my well water is 8-8.2
PH of my RO water is 8-8.2
I washed my medium in the well water 3 times and there was no red grit left in it.
I have added a full week of AN Veg at 1/2 strength (6 oz ea of Grow, Micro, and Bloom)
No O2 generator (and have turned off the air because it seems to keep the PH more stable)
Not chilled (water temp is 65-68) because res sits outside tent.
 
I got some Gold Blue ph down and used it to drop the ph (I have a gallon of regular ph down on order)
I used liquid ph down as well and my ph in theh res would climb up. I think the ph degraded inside the container overtime. Try Earth juice natural ph down (solid crystals) should hold the ph down in the res.
https://www.amazon.com/HydroOrganics-HOH84021-0-8-Pound-Organics-Supplement/dp/B0052TF4OG/ref=pd_lpo_sbs_86_t_0?_encoding=UTF8&psc=1&refRID=T94JDT0FF6WWB0JQGPXN
 
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AN is known for having big PH fluctuation .. if you do a search on them , most and even AN rep will tell you to leave the PH alone when using the Nuts .. might want to check on that ...

Also what is you res temp ?
 
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I'm gonna say your PH meter is toast. You are getting the same PH readings from the tap at 450ppm as you are at 20ppm after R/O. Not a good sign. The PH of R/O water should ideally be close to 6 if your system is functioning properly.
 
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Nope it's not. Well, not necessarily.

Regular pH meters can't measure solutions with very low ppm like ro water, you would need a special electrode for that. The reading a regular meter gives in such solutions means absolutely nothing, you could as well roll dice to get a value...
 
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And yeah, corells.
Hate them and love them.

I have a suspicion:
Grab a handfull of preferably fresh corells, get a Glas full of nutrient solution, pH it to 4 and throw them in there. If I'm right it'll be up above 7 in a couple hours.
Sometimes hydroton takes forever to get stable pH wise. I drenched a sack of this stuff for 5 days, dropped the pH below 4 a couple times per day and used it with way too high pH in the end.
Its foamed with calciumcarbonate for horticultural use I think, and it's known to take one or two grows to get "run in" and stable. It's not about the dust, new corells need soaking and pH correcting more than rockwool or anything.
New Corells suck, used corells rock!

If it's not the corells it's the water.
Did you try using ro water or 80/20 tap/ro?
If you'd like to know why your pH is generally climbing with tap/well water, the faster the more agitation you got, its the CO2 being driven out.
If you know how much carbonate hardness you got you can calculate how much acid or ammonium you'd need to neutralize the carbonate hardness and get a stable solution.
 
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Nope it's not. Well, not necessarily.

Regular pH meters can't measure solutions with very low ppm like ro water, you would need a special electrode for that. The reading a regular meter gives in such solutions means absolutely nothing, you could as well roll dice to get a value...
Maybe not a reliable reading at 20ppm but you should definitely see a difference between tap with 8.2ph and R/O.

@GoodGuy118 Can you tell us how your meter was calibrated?
Whether the test of R/O was done with just R/O before the introduction of media?
and as @Ikkt suggested test the media as he described.

I agree Co2 off gassing will raise PH slightly. But not that much. You would have to inject Co2 into the water to account for 2PH drop and a lot of it with little agitation just to hit that range.

I agree the media would be in all likelihood the culprit if the PH meter is good. I prob jumped the gun on this a bit
 
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I understand what you are saying pretty well.

Although 1 degree hardness is not really an accurate term as general hardness and carbonate hardness are not the same. KH (carbonate hardness) and GH (general hardness) are both measured in degrees (DH is a measurement).

Co2 off gassing from water only continues to the point of equilibrium, more agitation will not remove anymore so the speed at which this happens is a moot point in hydroponics. Co2 will reach equilibrium in hydroponics usually well within 12-24hr if not faster without agitation. That process is sped up with agitation but like i said this is a moot point in hydro.

Now the amount of PH drop that Co2 is responsible for depends on the source amount of Co2 above equilibrium in the water. I'm saying to get a 2 PH increase from off gassing Co2 is highly unlikely unless this is mechanically accomplished intentionally. Equilibrium is roughly 4ppm (roughly because there are a lot of calculations to be considered but i'm sure you understand this) at a 2 PH drop you are looking at about 400ppm difference which is very hard to believe.

It's far more likely the PH change is due to high KH buffering capacity of the water or something in the water and i'm guessing the air is speeding up that change due to the agitation. Like pouring salt in water it dissolves a lot faster when stirred or agitated.

Also do not use sulfuric acid as it has been linked to cancer (its battery acid). If you are using a lot of acid the best bet is R/O. Phosphoric does the better job at holding PH stable than nitric but using both is a good idea when using lots of acid.

Which leads me to back to my statement of I thought it was your PH meter. IF your RO unit is working properly your KH should be low and the buffering capacity of your water should be low. Meaning your PH should be lowered easily. Usually with a very low KH you see a PH crash not spike. Something is not adding up with the info provided i'm suspecting.

I guess the post i was responding to was deleted?
 
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Yes, seems its been deleted?!
No idea why, can't think of a good reason.
Was a little chaotic but besides that I don't know what's the problem.
To be clear the part about neutralizing carbonate wasn't directed at you specifically, it's just in general something everybody involved with growing crops should know about I thought.

And dH (not DH or dGH) means deutsche Härte, "German hardness".
Got it confused with dGH. It's an obsolete unit for general hardness, thought it is KH and in international use.
I get the difference between permanent and temporary hardness ;)

So yeah, in general I get what you say.
But it's been nearly two decades now and it's getting hard sometimes to get it all together.

What equilibrium do you mean?
There are a some involving CO2.
Sometimes hard to wrap my head around such stuff in second language.

I think, as you said too, it's the carbonate "buffer". But either you or me got something wrong.
Or we've got a misunderstanding.
As I recall you got HCO3¯, with addition of the H+ of an acid you get Water and CO2.
Because the equilibrium H2CO3 - CO2 is way on the right side and only minute quantities of carbonic acid are formed you'll have the CO2 gasing off. The faster the more you agitate. As both, carbonic acid and solute CO2, react acidic your pH rises as the CO2 leaves the water and your acid has been neutralized.
That's the CO2 I meant, coming from the neutralized carbonate.
And cause at our conditions there isn't much carbonic acid that's all there is to the carbonate buffer. Or not?
It's important as a buffer in our Blood but in nutrient solutions in my experience less is always better and straight ro with nutrients free of carbonates is best.

And as I said in the deleted post my tap water does exactly that till the point is reached where there's only ~30ppm HCO3¯ left. So I can either pH it to 5.5 and have it rise to 6.5+ two to three times a day for a couple days or just put in the calculated amount acid to break the carbonate buffer and leave it bubbling for a couple hours.
And with 400ppm carbonate in the water why shouldn't a couple hundred ppms CO2 leave the solution?
If they aren't what's happening with it?


About the sulfuric acid, I looked and found nothing of concern. Inhaling sulfuric acid mists heightens the chances of lung cancer, but so do other mineral acids as well and you shouldn't inhale acid fumes anyway.
If you do, lung cancer is the least of your problems I'd say ;)
So until I see new information on that I stand by my recommendation, sulfuric acid is great for pH adjustments but best is a combination of nitric, phosphoric and sulfuric acid.
And you should get clean sulfuric acid, I've got no idea if acid sold as electrolyte for lead accumulators has harmful contaminants.
Some people i know took the advice and like it a lot.


So, on topic and things not adding up:
He has those problems with well/tap water and just set up an ro unit if I got it right. So most probably those problems will be solved with that. If not that would be quite puzzling.
And I think I may be wrong on the corells, usually there aren't enough in dwc to cause something like that with those little net pots. Let's wait and see what Goodguy has got to say to that.

(Sorry if it's chaotic and poorly written, not a good day today...)
 
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Yes, seems its been deleted?!
No idea why, can't think of a good reason.
Was a little chaotic but besides that I don't know what's the problem.
To be clear the part about neutralizing carbonate wasn't directed at you specifically, it's just in general something everybody involved with growing crops should know about I thought.

And dH (not DH or dGH) means deutsche Härte, "German hardness".
Got it confused with dGH. It's an obsolete unit for general hardness, thought it is KH and in international use.
I get the difference between permanent and temporary hardness ;)

So yeah, in general I get what you say.
But it's been nearly two decades now and it's getting hard sometimes to get it all together.

What equilibrium do you mean?
There are a some involving CO2.
Sometimes hard to wrap my head around such stuff in second language.

I think, as you said too, it's the carbonate "buffer". But either you or me got something wrong.
Or we've got a misunderstanding.
As I recall you got HCO3¯, with addition of the H+ of an acid you get Water and CO2.
Because the equilibrium H2CO3 - CO2 is way on the right side and only minute quantities of carbonic acid are formed you'll have the CO2 gasing off. The faster the more you agitate. As both, carbonic acid and solute CO2, react acidic your pH rises as the CO2 leaves the water and your acid has been neutralized.
That's the CO2 I meant, coming from the neutralized carbonate.
And cause at our conditions there isn't much carbonic acid that's all there is to the carbonate buffer. Or not?
It's important as a buffer in our Blood but in nutrient solutions in my experience less is always better and straight ro with nutrients free of carbonates is best.

And as I said in the deleted post my tap water does exactly that till the point is reached where there's only ~30ppm HCO3¯ left. So I can either pH it to 5.5 and have it rise to 6.5+ two to three times a day for a couple days or just put in the calculated amount acid to break the carbonate buffer and leave it bubbling for a couple hours.
And with 400ppm carbonate in the water why shouldn't a couple hundred ppms CO2 leave the solution?
If they aren't what's happening with it?


About the sulfuric acid, I looked and found nothing of concern. Inhaling sulfuric acid mists heightens the chances of lung cancer, but so do other mineral acids as well and you shouldn't inhale acid fumes anyway.
If you do, lung cancer is the least of your problems I'd say ;)
So until I see new information on that I stand by my recommendation, sulfuric acid is great for pH adjustments but best is a combination of nitric, phosphoric and sulfuric acid.
And you should get clean sulfuric acid, I've got no idea if acid sold as electrolyte for lead accumulators has harmful contaminants.
Some people i know took the advice and like it a lot.


So, on topic and things not adding up:
He has those problems with well/tap water and just set up an ro unit if I got it right. So most probably those problems will be solved with that. If not that would be quite puzzling.
And I think I may be wrong on the corells, usually there aren't enough in dwc to cause something like that with those little net pots. Let's wait and see what Goodguy has got to say to that.

(Sorry if it's chaotic and poorly written, not a good day today...)
Ok forget all the scientific calculations here for a min.

1.He is getting a PH of 8.2 out of the tap and a PH of 8.0 after R/O
2.He is using PH down to bring it down to a PH of 6.
3. PH down is not carbonic acid, his PH down is likely Phosphoric/nitric acid mix or just phosphoric.

He is seeing an increase of PH by 2, back up to his original PH after a few hrs. which you are accounting for Co2 off gassing, or the reduction in carbonic acid. Keeping it simple like you said when carbonic acid is neutralized it leave the water as Co2

So where is all this carbonic acid coming from since it was not added? Thats a massive amount of cabonic acid to make a 2 point difference in PH and would require a shit ton of dissolved Co2 close to 400ppm ( I injected Co2 into my planted tanks running about 40ppm and i used a Co2 reactor in order to do so). Just like when phosphoric acid is broken down the PH rises and same with nitric etc. This is why certains acids work better to adjust PH and last longer.

So to get a 2 PH increase and claim its due to Co2 is not very likely.

Its also highly unlikely thatr his PH meter and R/O unit are both working properly because R/O water should have next to 0 buffering capacity and a small amount of PH down should easily bring the PH down and stay down if not crash. Not spike.

So in all likelihood i am assuming either his PH meter is garbage or his R/O unit is not working.
 
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I can see how this could be attributed to the nutrients depending on their contents or source water but not from off gassing Co2.
 
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My well water tests at 8. I dropped the ph down to 6. Within hours with the air on, the ph was rising. I added 1/2 strength AN nutrients after getting it “in the zone”. It will rise all the way to 8.5-8.7 within a day. I got some Gold Blue ph down and used it to drop the ph (I have a gallon of regular ph down on order). It climbs back quickly with the air on, but if I turn the air off, it climbs much more slowly. It has stunted (if not killed) 2 of the plants and seems to have stunted the others as well. I bought an RO Buddie and am ROing a 55 gallon drum of water. When I test the RO water, the ph is still 8.0 after the RO but the PPM drops from 450ish down to 20ish. Any thoughts/recommendations?. TIA
Ok this was buggin the shit out of me and i think i got this figured out after looking into your R/O unit. The R/O buddy does not come with the R/O membrane. It needs to be purchased separately and installed by you.

Do you have a water softener? I get the feeling with 8.2 PH that you do and it uses sodium bicarbonate. Most water softeners produce water with a PH of about 8.2. This would make sense to me.

Let me know if that the issue.

Dan
 

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