# sodium hydroxide as ph up?



## troy (Jan 27, 2015)

General hydropnics 'maxi gro' one of my rotation ferts. Drops my ro water ph when mixed to a 3, will raising ph with sodium hydroxide do damage? Or does anybody here have any suggestions? Any will help, thanks


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## PaphMadMan (Jan 27, 2015)

Sodium hydroxide is certainly the active ingredient in some pH up additives for hydroponics and aquariums. Nothing else is cheaper or more effective.

To be on the safe side you might want to calculate what ppm sodium you end up with, other than that there is no possible harm other than to you in handling caustic. Use a sodium hydroxide solution, not the solid. And you will monitor pH of course.

On the other hand, unless you are in a hydroponic system with no organic material in your mix, or your fertilizer solution is outrageously high ppm itself, the media probably buffers the pH above 5 anyway.


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## ALToronto (Jan 27, 2015)

You're much better off using Pro-Tek, which is a potassium silicate and will give you additional benefits.


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## troy (Jan 27, 2015)

Using a low ph fertilizer say 4.0 or 5.0 wouldn't hurt? I thought the medium lowers ph?


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## Brabantia (Jan 27, 2015)

ALToronto said:


> You're much better off using Pro-Tek, which is a potassium silicate and will give you additional benefits.


Yes but it adds Potassium which is not always wished. 
I calculated that 3 - 4 drops of KOH one mole per liter (1 M) add 6 - 7 ppm of K. It is the quantity of the 1M KOH solution that I must add to 1 liter of the usually used mineral fertilysers which contain about 300 mgr / L of these (~ 40 ppm N). 
For your information: a KLite solution at 40 ppm of Nitrogen contains 3.3 ppm of Potassium. The neutralization of these solution to pH 6 augments the K content considerably. 
To neutralize the fertilyser solution a better method is to use tap water. In my country here in Belgium we have very hard water (44 °F). I need only add 25 ml /L of tap water in order to reach a pH of 6. Of course I have diminished the fertilyser content in order to hold a total conductivity of around 300µS and augmented the fertilyser distribution frequency. Working so I add only Ca and Mg and maybe some elements which are not present in fertilysers.


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## troy (Jan 27, 2015)

Wouldn't The usable elements in fertilizer be overtaken by the solids in tap water I think the tap ppm is like 500


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## gonewild (Jan 27, 2015)

troy said:


> Wouldn't The usable elements in fertilizer be overtaken by the solids in tap water I think the tap ppm is like 500



You just need to adjust your fertilizer to balance it.
Your tap water with 500ppm most likely has all the calcium you need and solves your pH problem. 
And it probably only will take a small amount of tap water to raise the pH a couple points.


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## troy (Jan 27, 2015)

I'll try that, my ph up is 100°/. Pure sodium hydroxide, very strong , there was no molarity percentage so I stuck my finger in it and yep it burned my finger, so 8 drops of this stuff per gallon is worse than using tap?


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## PaphMadMan (Jan 27, 2015)

troy said:


> Using a low ph fertilizer say 4.0 or 5.0 wouldn't hurt? I thought the medium lowers ph?



Organic medium buffers pH - tends to pull it toward whatever the natural balance of the mix is. So if the mix is naturally 6, whether your fertilizer solution is 8 or 3, the medium tends to stay close to 6 once it equilibrates as long as your solution isn't too concentrated or too highly buffered itself.


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## TyroneGenade (Jan 27, 2015)

KHCO3... Won't raise the pH above 8.4 but will neutralize the acid.
Another alternative is KH2PO4 which would stabilize the pH around 7.2 (probably less, closer to 6 as it is a weak base).

Side effects: both the HCO3 and the PO4 will reduce calcium solubility... but you won't burn your fingers or your plants. Regular washing should prevent the build up of K in the substrate.


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## Silvan (Jan 27, 2015)

and what you guys think about the Potassium Hydroxide sold has PH+ in hydro stores ?


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## TyroneGenade (Jan 27, 2015)

I have no issue with KOH other than it can be dangerous in concentrated form. When the granules dissolve they get hellishly hot so that is another danger... I prefer the idea of a weaker base.

If you add 1 g of KOH per L then you add 1.7 g of KHCO3 per L instead.


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## cnycharles (Jan 27, 2015)

Couldn't you use baking soda to raise water pH?


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## ALToronto (Jan 27, 2015)

Why would sodium be less bad than potassium? At least K is a nutrient, arguably over-applied. Sodium is a contaminant with no redeeming qualities.

Troy, your initial post reminds me of a quote from a very wise man: "The more precisely a problem is stated, the more likely it is to be the wrong problem". I suspect that your problem is the fertilizer you're using, both the composition and the concentration. In all our fertilizer discussions on this forum, I don't think anyone had to contend with such a low pH.

Maybe you should revisit your plants' diet rather than increasing TDS with a hydroxide.


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## Bjorn (Jan 28, 2015)

I think I should add a comment to this! Being a chemical engineer of profession, my advice isto stay away from concentrated sodium and potassium hydroxides! They are potentially dangerous and willat a minimum cause your skin to crack with extended contact. Some much better solutions have been proposed here already, what about intermixing with well water if it is available? Or baking soda? Baking soda, sodium hydrogen carbonate is commonly used as an carbonate-up in 
aquariums.


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## troy (Jan 28, 2015)

Thanks for all the info!! there are alot of options to take in


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## Stone (Jan 28, 2015)

For organic mixes you use lime or dolomite. Just like all the best grows have for 100 years.


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## myxodex (Jan 28, 2015)

As Brabantia says, tap water is the simplest if it is suitable. My advice is get a tap water analysis from your water provider.


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## DavidCampen (Jan 28, 2015)

Diammonium Phosphate (DAP) will raise the pH more gently than a potassium hydroxide based pH Up preparation and it works as a pH buffer.

http://www.amazon.com/Diammonium-Ph...22474788&sr=8-6&keywords=diammonium+phosphate

Does someone actually sell a pH Up made with sodium hydroxide?


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