# Controlling PH for Hydroponics/Aeroponics



## Damios (Dec 6, 2008)

As many know, PH is much more of a concern for growers who decide to use hydroponic and aeroponic systems. Not only do your plants get affected quicker when you have a PH problem in hydro or aero, but the PH of your rez itself fluctuates (usually rising) throughout the day creating more of a chance for problems to occur. Along with this, the larger your plants get, the more and more your PH usually goes up throughout the day. This thread is to show and explain ways to maintain your PH in your systems reservoir, using PH controlling/dosing systems or by buffering your water using certain chemicals. Feel free to post with any input pertaining to this.


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## Damios (Dec 6, 2008)

http://www.stealthhydroponics.com/product.php?xProd=135&xSec=27

This is a cheap but effective PH dosing kit from stealth hydroponics. I will be the first to say that SH isn't that good of a company when it comes to ANY of their products, expecially lighting, but for the cost and the effectiveness of this item it is worth it. The only other product your going to find that automatically doses your PH to the level you want is going to cost $700 from just about anywhere. This thing is also probably only good for one rez (seeing how you only get one diffuser) and nothing over 25 gallons, although you could always switch out the 5 gallon bucket that comes with the kit and use a larger bucket, maybe 10-20 gallons, that way your PH solution wouldn't run out nearly as fast if you use a lot.


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## Damios (Dec 6, 2008)

Earl if you are reading this, I saw a post where you explained how to buffer your nutrient water so that you rarely need to change your PH, it would be awesome if you could explain it. If I find the post I will just paste it in here.


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## caddy (Dec 6, 2008)

I check mine twice a day, a.m & p.m - I find by slightly micro-managing the PH I ensure total stability and environment control. I'm a new grower in hydroponics so I take nothing for granted, if the veteran gardeners say keep it at 5.8 +/- .1, that's what it shall be.

As for what I use - TechnaFlora PH down, only. As for fancy ways to buffer the water I really don't have any information on that except by the twice daily checking I find very seldom the need to do much, if any, intervention at all. If I do its by very few ML of PH down just to get it spot on 5.8- I've had my system run 6+ days and never creep out of range by more than a half point. 

Definitely interested in the Earl thread if you can find it, would love to read that.


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## MuntantLizzard (Dec 6, 2008)

i got some organic stuff...I would reall like to see that thread about buffering, link plz


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## Bubba Kushman (Dec 6, 2008)

I use ph bufered nutes to avoid ph issues. But I have personally found that the EC is the most important in hydro. If the EC gets too high you can kill your plants overnight. Its more forgiving if the ph is off a bit. The ph has to be right in soil or you get very slow growth and low yield.


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## Damios (Dec 6, 2008)

Bubba Kushman said:


> I use ph bufered nutes to avoid ph issues. But I have personally found that the EC is the most important in hydro. If the EC gets too high you can kill your plants overnight. Its more forgiving if the ph is off a bit. The ph has to be right in soil or you get very slow growth and low yield.


This thread is assuming you have your ppm's where you want them, with that in mind, you would want your PH to be as spot on as possible so they can get the most out of the nutes you give them.


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## GreenThumbSucker (Dec 6, 2008)

Im new to hydroponic growing, but I can tell ya what out of control PH can do...

Mine went up to 7.0 for a day or so and wreaked havoc on my plants. All the new growth on my plants started coming out looking like long skinny spider legs. My plants elongated like palm trees. It looked like a weeks worth of damage in 24 hours. 

Fortunately, the magic of hydroponics works both ways. Yesterday I changed out the water in my system and put the PH in the high fives and BOOM! they took right off, back to normal elongation and growth. Today, 24 hours after fixing the PH, they are back to full growth. The new leaves look completely normal, like magic.

I imagine that two or three days with PH that high might have damaged them to the point that I would have to tear them out and start over.

I will definately be following this thread....


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## cannabiscrusader (Dec 6, 2008)

i read somewhere on this site that plants take up nutrients and macro nutrients in higher concentrations under different ph levels. Also that the fluctuation of ph levels increacing though the day is natural and allows the plant to fully utilize the nutrients available. 

Again just something i read on here


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## Damios (Dec 7, 2008)

cannabiscrusader said:


> i read somewhere on this site that plants take up nutrients and macro nutrients in higher concentrations under different ph levels. Also that the fluctuation of ph levels increacing though the day is natural and allows the plant to fully utilize the nutrients available.
> 
> Again just something i read on here


Yes, PH affects the amount of nutrients that are able to be absorbed, and yes also some nutrients are only able to be absorbed at certain PH levels.

Here's a good quote on ph from:
http://www.usna.usda.gov/Gardens/requirements.html

"The ability of plant roots to take up certain nutrients depends on the pH, which is a measure of the acidity or alkalinity of your soil. Most plants grow best in soils that have a pH near 7.0. Most ericaceous plants such as azaleas and blueberries need acid soils with pH below 6.0 to grow well. Lime can be used to raise pH and materials containing sulfates such as aluminum sulfate and iron sulfate can be used to lower pH. The solubility of many trace elements is controlled by pH, and only the soluble forms of these important micronutrients can be used by plants. Iron is not very soluble at high pH and iron chlorosis is often present in high-pH soils, even if they contain abundant iron." 
http://www.usna.usda.gov/Gardens/requirements.html 
And yes rising PH levels are natural, the more nutrients the plants take up the higher the potential hydrogen of the water will increase. Although, having your PH stay at a specific level is what allows the plant to better work with the nutrients avaliable.


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## cannabiscrusader (Dec 7, 2008)

glad to find out i still pay attention now and again


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## Damios (Dec 7, 2008)

I finally found the post so here it is.



Earl said:


> It is not necessary to adjust the pH
> if you have your solution properly buffered.
> 
> I can go for weeks without any adjustment,
> ...


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## delstele (Dec 7, 2008)

Damios said:


> I finally found the post so here it is.


Cool thanks for the info..kiss-ass


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## Earl (Dec 7, 2008)

If you are using a nutrient solution that calls for Potassium Silicate,
do not add it,
until the pH starts to fall.

Once you reach the max dose for Barricade(0.4ml/gl)
then you can start using the Potassium carbonate/hydroxide(pH up) 
until the pH is stable.

Barricade, Silica Blast, Dutch Master Silica,
are all Potassium silicate,
and they will raise the pH.

Once the pH is stable 
it might go up if the TDS goes down,
but if you don't have any leaks 
the pH will be stable 
as long as you only add pure RO 
to keep the rez full.

When I am doing this,
I rely on a fast pH meter 
and I use an eye dropper to dose the solution.

If you have tested the pH of your RO,
then you have probly slowed down your meter.

Never put your pH probe into RO,
it slows down the response time dramatically.

You need to add RO to your rez 
and make sure the level is the same every time,
before you measure and adjust the pH.

I am assuming your RO is under 10ppm


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## Damios (Dec 7, 2008)

Awesome thanks again Earl.


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## MuntantLizzard (Dec 7, 2008)

where do you look up the buffered nutes?


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## Earl (Dec 8, 2008)

There is no way to buffer a nutrient solution in one bottle.

You have to mix up your nutrients 
and then buffer them 
so the acid will be kept at the pH level you desire.

You should not be chasing the pH up and down.

Buffering is done by molecules that are able to give up Ions.
Several different Potassium molecules are good to use for this purpose.

Using them in combination 
will give you the longest duration of stability,
without reaching toxic levels.


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## MuntantLizzard (Dec 8, 2008)

I got ya, I think. mix em up and let em sit and watch for the ph to stay?


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## MonstroniuM (Dec 4, 2009)

Can someone put earls buffering stuff in stoner lameman terms?


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## odin92681 (Dec 4, 2009)

I'm subscribing. I see how it can be a chore adjusting the PH daily but I don't mind so much, yet.


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## snutter (Dec 4, 2009)

Damios said:


> As many know, PH is much more of a concern for growers who decide to use hydroponic and aeroponic systems. Not only do your plants get affected quicker when you have a PH problem in hydro or aero, but the PH of your rez itself fluctuates (usually rising) throughout the day creating more of a chance for problems to occur. Along with this, the larger your plants get, the more and more your PH usually goes up throughout the day. This thread is to show and explain ways to maintain your PH in your systems reservoir, using PH controlling/dosing systems or by buffering your water using certain chemicals. Feel free to post with any input pertaining to this.


I'm sorry but I'll have to disagree. I grow DWC hydro, and my girls are in day 23 of flowering. And if there is one thing I notice more than anything about my pH, it's that they are drinking about 1 gallon of water a night, and my pH goes DOWN, not up....

Just thought I'd throw that out there. It's not a problem for me, however. Once I add a fresh gallon of water, my pH goes right back to where I like to keep it, about 5.5... My tap water pH is about 7.1.


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## fatman7574 (Dec 4, 2009)

By Earl
It is not necessary to adjust the pH 
if you have your solution properly buffered.

I can go for weeks without any adjustment, 
after I have buffered my solution.

I just add plain RO, 
with no pH adjustment, 
and my pH is perfect at 5.6
That's only because the nutrient mix is naturally pH balanced at 5.4 to 5.6 on nearly all chemical hydroponic nutrients and because RO water has no buffers so it becomes what ever pH the nutrient formulation makes it. It you did not obtain that pH you have problems with excessive CO2 in the RO water. You will never have a high pH with RO mixed nutrients if they were properly formulated.

There are four agents that you should use 
in the correct combination 
to get your solution to the proper state of buffer.

&#8226;Phosphoric acid Not
&#8226;Potassium Silicate Not
&#8226;Potassium Carbonate Yes
&#8226;Potassium Hydroxide. Not

This can only be done with RO or Distilled water,
and a digital pH meter so you can maintain 5.6.
Any water can be buffered.

Use the P-silicate first, 
Wrong. This will raise the pH but not add any buffering. Meaning if you use it to raise the pH then you can not also use the P-carbonate and P-hydroxide as then your pH will be excessive. If he is just indicating adding a little Pottasium silicate, why. The use of pottasium silicate is recommended for other reasons. Some people wrogly use it as a long term pH up. That is a waste of monet y and means less use of pH up which at least contains some buffer.
and then the P-carbonate & P-hydroxide in combination. 
Earl the P-carbom nate in pH up should be the primary used ingrediant in you scheme as it is the only buffer you even mention.


Right Earl. P-carbonate and p-hydroxide are the active ingediants in pH Up. Hopefully people know that, if not they now do, no thanks to you. But they should be used as the pH up and buffer as potaasium silicate does not contain a buffer. It contains about enough P-carbonate to buffer only as long as it took to reach the lower pH your now adjusting for. They only added enough buffer equivalent in neutrlizing power (buffering ability) equal to the amount of acid which caused the need for the pH up. So if your sytems pH khad previously dropped the amount your now adjusting in 12 hours the pH up will last twelve hours. If the pH drop happens over 24 hours the PH up P- carbonates will last about 24 hours. Tye pH up manfacturers are intentionally only supply a temporary fix. Anything more than that would reduce sells of pH Up. They definitely want you to buy more rather than less. They are not your friends they are money makes. They want your money, not appreciation.

It takes about four days of checking the pH, 
at least twice a day, 
to get the solution properly buffered, 
depending on whether the mfg of the nutes 
you are using has already buffered the nutes.
What are you now even trying to say Earl. Are you simply confusing simple adjusting of pH with buffering against acids by adding carbonates above your present daily usage. You make little sense Earl and provo ide no information other than galzing over pH adjustments daily for a few days.

If you have unbuffered nutes, 
then you may not need the Phosphoric acid. 
If someone has unbuffered nutes they will have no problem obtaining a low pH. Duh!

Once you learn to buffer your solution
you will have less pH fluctuations.
But you taught no one how to buffer their nutes Earl, unless you consider using pH up buffering nutes. It is a vey, very temporary buffering. If you have long term acid accumaltaion then you need long term buffering. pH up does not provide that long term buffering.

What a numb nuts. Guys I hate to burst the bubbles of those who think what Earl wrote is going to change much because as usual he doesn't really know much about what he is writing about. I have read many of Erals posts where he whined about his continual pH problems. By the looks of this entry he is taill han ving problems ass nothing he has written adequately adresses the problem of a lack of adequate buffers.

To begin with adding an acid or a hydroxide typically only lowers or raises your pH it does not buffer. Acids are what you buffer against, not what you bi uffer with. You can not readily buffer against hydroxide influence on Ph. Unless the hydroxide forms up with something to make a strongly bound carbonate it does not contribute to acid buffering. Carbonate and Bicarbonates can buffer but they are pretty poor buffers as they are essentially just calcium carbonates waiting to become attached to a phosphate, sulfate, magnesium etc. in order to become a permanent hardness buffer. In the mean time all they really buffer aginst is a carbonic acid formed by excessive CO2 in the water. That is not a common problem in aerated fresh water nutrients. 

Silica phosphate does not buffer. The silica is pretty much inert as far as affecting the pH or buffering, however the potasium it was bound to is a hydroxide so its addition will temporaily raise the pH unless it binds with a carbonate then it will not appreciably effect the pH but will instead form a buffer (pottasium carbonate). However the calcium must be there for it to bind with. Phosphoric acid will not buffer at all either but it is an acid and it will lower the pH so it is a reason for needing a buffer. 

The only buffer (carbonate buffer) Earl even mentioned is the pottasium carbonate. It is not a very good buffer, but fair as it does do a small amount of buffering. Magnesium carbonate is a good buffer. Sodium carbonate and sodium bicarbonate (half as effective as sodium carbonate) are also just fair buffers as they might bind with magnesiun m or such and become a good buffer. 

The fresh water buffers are the carbonates which cause permanent water hardness not temporary water hardness (calcium carbonates such a sodium carbonate or sodium bicarbonate) are called temporary hardness. However the temporay hardness calcium can form up with magneisun, sulfate and phosphates etc. to form good buffers. For example soluble calcium from calcium nitrate or calcium chloride can bid easily with magneisum from magnesium sulfate or with pottasium to form buffers. 

Calcium carbonates by themselves are not a good buffers as they are weakly bound carbonates, just as sodium carbonate or sodium bicarbonates is not good buffers as they also must bind with a sulfate, magneisun or pottasium to become a good buffer.

In all reality if you want good buffering you must insure the minerals needed to form those buffers are in your nutrients. This essentially means you need calcium and magnesium at levels high enough to provide your plants needs for calcium and magnesium plus also supply enough calcium and magnesium to form the magnesium carbonates needed to form buffers. When this is low pH is most often a problem is in early growth when the plants are taking up ammonical nitrogen and therefore the roots are putting out H+ ions to balance the pH within their system, or during budding when the plants needs are high for magnesium and pottasium and when the plants are also doing the H+ releases.

While pH up does raise the pH and does supply a very small amount of a fair buffer it in does not supply enough buffer as it should. They know more is need but they just throw in a token small amount so that they can say they supplied buffer. Obviously they have no intent to supply adequate amounts. After all it pH up supplied adequate buffers for long term buffering no one would ever have to buy more as they would have to only use just a little very seldom.

Essentially if you have a problem with your pH continously dropping you should add more magnesium sulfate and calcium. Yu should also look at your fertilizer ananysis and see how much ammonical nitrogen is in the formula. If it is more than about 10% of the amount of total nitrogen you need to buy a different formula as it will lawys have low pH problems in early veg and in bloom.

There is a product called something like Cal-Mag on the market that is an excellant way of handling the issue. SH Hydroponics, Inc. > Botanicare CAL-MAG Plus&#8482;

If you esearched you would find that there are two types of Calcium Nitrate fertilizers on the market. When one is made Lime is used to precpitate the fertilizer. This forma Calcium Nitrate fetilizer. When the other type is being made dolomitic lime (mah gnesium carbonate) is used and this acused a precpitated fertilizer of Calcium Nitrate with magnesium carbonate and some iron attached. 

When you see a calcium nitrate fertilizer that also lists some thing like 30% magnesium in its analysis it is what is being sold as Cal-Mag. It add a great amount of buffering power but it also adds Nitrate. A formulation made by most commercial hydroponics growers for the fruiting (budding state) uses Calcium Nitrate with magneisum in its formulation rather than Plain Calcium Nitrate. AN and GH does not do thais as many customers use tap water and the combination of hard tap water and a formula with a lot of magneisum carbonates would really suck as most of your EC would be in carbonates not the other nutrients. 

You very seldom can get what you need or want by buying commercilal nutrients as they sell to the masses and therefore sell a poor product in reality as they are trying to put out one products to work for a hugh vareity of needs. With self mixed you prepare just what you need not what the average of the masses might be able to get by with.

As far as saying adding a little pottasium carbonate is going to solve your problem for more than a day or that anything else Earl suggests is going to solve your problems. NOT. RO water has no buffers. Period. Adjusting your pH and adding some Pottasium carbonate as in adding pH up is not going to solve a long term problem of a lack of aedquate permanent hard water carbonates. Alkaline water is water full of buffers. Nutrient manafacturers don't sell any highly alkaline major nutrient formulations, as they sell a minimum amount of carbonates in the formulations they sell as they are not considered nutrients, and because it would reduce the sell of their other products that are sold to address pH issues. Remember they are not your friends they are your dealers out to get as much of your money as they can. They really don't need or even care about your appreciation praise or word of mouth advertising as you are a captive consumer group. There are very few Pot nutrient manafacturers in comparison to regular nutrient manafacturers. They know you have no waher else to go to get what you want. The only highly alkaline nutrient commonly sold that I am aware of is Cal-Mag (Calcium Nitrate made with Dolomitic Lime) sold as a *supplement*.


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## edwardtheclean (Feb 16, 2010)

good info, thanks guys


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## WaRpIg (Aug 2, 2010)

CAN CO2 BE INJECTED INTO THE water or a aero system to control PH? I have read where they use it for aquariums but I have seen nothing about using it for aero systems.


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## Harrekin (Aug 2, 2010)

Is it true with Advanced Nutrients you can just measure out the nute levels and dump it into the water and the pH level sets itself?


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## WaRpIg (Aug 2, 2010)

Yes Advanced can only if you follow it ..


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## asbonasty (Aug 12, 2010)

Ok fatman7574, so to clarify, if my ph keeps dropping and my ppm of my tap water is around 70??

If I was to add calcium and magnesium sulphate, what ratios of each would I add? I could measure the ppm to get to around 200 to get good buffering.

You say magnesium sulphate, but what type of calcium would I add? Calcium carbonate? My understanding would be that the carbonate would then bind with the magnesium "? Or am I completely off?

asbo


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## ogreballerina (Dec 17, 2010)

Harrekin said:


> Is it true with Advanced Nutrients you can just measure out the nute levels and dump it into the water and the pH level sets itself?


I wish...

When your set up is clean and new it does...but as salts build up in the medium it can change.
You would have to flush it thoroughly every week or so and add new nutes to hit the that magic number. 5.5 to 5.7

I used Advanced Nutrients and for the most part is stable...but some days it can throw you on a wild ride...chasing that perfect PH.

I've woken up in the morning and had it read in the high 3s...and took 2x times the RO water that was lost to evaporation and plant growth to fix it. Other mornings it seems just fine. Go figure...

Buy a PH tester regardless..and test every day.

The PH will shift throughout the day regardless...mid 5s to low 6 is how I roll.


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## phenob (Jan 9, 2011)

fatman7574 said:


> By Earl
> It is not necessary to adjust the pH
> if you have your solution properly buffered.
> 
> ...


this post might be over a year old, but that's damn good PH knowledge right there. Wish i had seen this earlier. Thanks FatMan.


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## MightyZeppelin (Jan 12, 2011)

phenob said:


> this post might be over a year old, but that's damn good PH knowledge right there. Wish i had seen this earlier. Thanks FatMan.


I'm not positive but I think FatMan7574 got booted from this site.


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## chronic case (Feb 25, 2011)

The info in this thread is great, but seems to be more useful for growers with low ph problems. I'm hoping someone can help answer my problem. I am having a hell of a time with my ph keep jumping up to nearly 8. I let my tap water sit out for several days and bring down the ph to 5 with vinegar. Temps in my grow box are finally staying stable from 65-85. Should I just start buying RO water? Or is it the vinegar that is my problem? 
FYI: I am using a homemade version of the Original DWC. I have a 600HPS going 24/7 over a Jilly Bean and Botafumeros. Plants are only about 8 inches so far and started from seed about 6 wks ago. Roots are doing well though. I can feel the hairs if I reach under the net pot. I plan to scrog, if they ever start stretching out.


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## skunkd0c (Feb 27, 2011)

i stoped taking ph readings about 10 years ago but i do add some phosphoric every once in a while just incase it might help it or something not noticed any difference though
my water supply is always constant at 4cf 7.4ph once ive added the food it brings it down to around 6.5 or so 

a good quility food comes with ph buffers and micro nutes deliverd in the form of chelates to allow those elements to be availibe at much larger ph ranges 

i think obsession over ph is a thing of the past when food quility wasnt as good as it is today although a ph of 8 is high and probly wouldnt do them any good 

perhaps you should be using something stronger like phospheric acid thats at 90 odd % they even do nitric acid at 36% for ph reduction , using vinegar to lower ph is a bit ghetto

id go for the phospheric i would only need 5 ml of that per 50 litter res to lower it from 7-6 or 6.5 to 5.5 ..
the ph will change alot if your resevour is small , less than 20 liter or so dont worry about getting the ph as low as 5 as long as it on the acidic side you will be ok 6.5 is fine 6.0 is better 

some foods are overall more acidic than others i found canna would lower the ph well, 
currently im using vitalink, which also lowers the ph

not sure how you are measuring ph 
those low quility digital ph meters are useless, you are better off using the liquid colour/drip ph test kits


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