Controlling PH for Hydroponics/Aeroponics

Damios

Damios

Well-Known Member
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.
 
Damios

Damios

Well-Known Member
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.
 
Damios

Damios

Well-Known Member
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.
 
caddy

caddy

Well-Known Member
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.
 
B

Bubba Kushman

Well-Known Member
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.
 
Damios

Damios

Well-Known Member
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.
Click to expand...
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.
 
GreenThumbSucker

GreenThumbSucker

Well-Known Member
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....
 
cannabiscrusader

cannabiscrusader

Well-Known Member
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
 
Damios

Damios

Well-Known Member
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
Click to expand...
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.
 
Damios

Damios

Well-Known Member
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,
after I have buffered my solution.

I just add plain RO,
with no pH adjustment,
and my pH is perfect at 5.6

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

•Phosphoric acid
•Potassium Silicate
•Potassium Carbonate
•Potassium Hydroxide.

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

Use the P-silicate first,
and then the P-carbonate & P-hydroxide in combination.

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.

If you have unbuffered nutes,
then you may not need the Phosphoric acid.

Once you learn to buffer your solution
you will have less pH fluctuations.


.
Click to expand...
 
Earl

Earl

Well-Known Member
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
 
Earl

Earl

Well-Known Member
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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