DIY PH Down from Sulfuric Acid. (Battery Acid)

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Brunob

New Member
When it comes to using phosphoric acid and sulphuric acid to lower pH, is one better than the other?
I can get 5L of 76% sulphuric acid for $55 and 5L of 85% phosphoric acid for $28. Which on is better value? Will I need to use less of the sulphuric acid compared to the phosphoric acid to achieve the same desired outcome when lowering pH?
 
Budzbuddha

Budzbuddha

Well-Known Member
Brunob said:
When it comes to using phosphoric acid and sulphuric acid to lower pH, is one better than the other?
I can get 5L of 76% sulphuric acid for $55 and 5L of 85% phosphoric acid for $28. Which on is better value? Will I need to use less of the sulphuric acid compared to the phosphoric acid to achieve the same desired outcome when lowering pH?
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Why complicate things ? …. You literally can get a gallon of GH PH down for $20 bucks or so.

IMG_5424.jpeg
 
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nxsov180db

Well-Known Member
Brunob said:
When it comes to using phosphoric acid and sulphuric acid to lower pH, is one better than the other?
I can get 5L of 76% sulphuric acid for $55 and 5L of 85% phosphoric acid for $28. Which on is better value? Will I need to use less of the sulphuric acid compared to the phosphoric acid to achieve the same desired outcome when lowering pH?
Click to expand...
Not sure which one is a better value or but Sulphuric is a stronger acid, I use sulphuric because its cheap locally.
 
ttystikk

ttystikk

Well-Known Member
Brunob said:
When it comes to using phosphoric acid and sulphuric acid to lower pH, is one better than the other?
I can get 5L of 76% sulphuric acid for $55 and 5L of 85% phosphoric acid for $28. Which on is better value? Will I need to use less of the sulphuric acid compared to the phosphoric acid to achieve the same desired outcome when lowering pH?
Click to expand...
Phosphoric acid brings a more desirable nutrient and sulfuric acid in battery acid may not be food grade.

Where are you getting phosphoric acid so cheap?
 
B

Brunob

New Member
ttystikk said:
That's more what I was thinking. My concern about battery acid is whether it's food grade.
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I'm only growing tropical indoor plants so doesn't matter about food grade, but it's pure sulphuric acid with no impurities so I'm sure it would be
 
ttystikk

ttystikk

Well-Known Member
Brunob said:
I'm only growing tropical indoor plants so doesn't matter about food grade, but it's pure sulphuric acid with no impurities so I'm sure it would be
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Food grade is a big can of worms that you don't need to address if you're just growing decorative varieties.
 
7CardBud

7CardBud

Well-Known Member
If someone is looking for a cheap pure acid for pH down why not use muriatic acid? It's made by bubbling hydrogen chloride into deionized water.
The final product will always be a pure solution of water, hydronium and chloride.
 
Drop That Sound

Drop That Sound

Well-Known Member
I always wondered what they use, and if it is some special dye that is resistant to acid base. Like, what if they are using "methyl orange", and actually use it to visually inspect the product during a batch, or something of that nature..

Why orange? I mean, I kinda like it, and am totally accustomed to it. If I'm gonna mix up some battery acid, I kinda want to make it the same color as in those same bottles I'm used to handling, like GH has conditioned me into, lol. I don't wanna add a food color that might react in some bad way though, so was just curious. I guess its a trade secret..
 
Billy the Mountain

Billy the Mountain

Well-Known Member
Drop That Sound said:
I always wondered what they use, and if it is some special dye that is resistant to acid base. Like, what if they are using "methyl orange", and actually use it to visually inspect the product during a batch, or something of that nature..

Why orange? I mean, I kinda like it, and am totally accustomed to it. If I'm gonna mix up some battery acid, I kinda want to make it the same color as in those same bottles I'm used to handling, like GH has conditioned me into, lol. I don't wanna add a food color that might react in some bad way though, so was just curious. I guess its a trade secret..
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You could absolutely add a few drops of standard food coloring if desired. I've done so to minimize the chance of grabbing the wrong bottle.
I'm convinced the fear about using sulfuric acid is that it is more concentrated, hence dangerous, if you have a spill. If that's a genuine concern, simply dilute it.
 
Drop That Sound

Drop That Sound

Well-Known Member
On the other hand, not knowing exactly why pH UP/DOWN is blue and orange is all the more reason to DIY your own, and know exactly whats going into your mix. It seems more cloudy like tampico orange juice than really clear like hi-c or orange koolaid though. Thicker. More like they are using a powdered substance as the dye..

Either way, I will probably go ahead and add a few drops of food coloring and call it good ;)
 
Billy the Mountain

Billy the Mountain

Well-Known Member
7CardBud said:
Muriatic is dirt cheap at about $8 gallon....plus it makes a great toilet bowl cleaner:razz:
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It's probably fine for hydro in a pinch, but I've avoided hydrochloric acid because of the chloride. I haven't done the math the calculate Cl- ppm at typical pH-down concentrations. Cl is a micro-nutrient (at a few ppb) but is toxic to plants at higher levels, a mere 20 ppm is harmful.
I do concur it's amazingly effective removing hard-water stains.

A short article on chlorides and hydro:

What is the effect of chloride in hydroponics? – Science in Hydroponics

scienceinhydroponics.com scienceinhydroponics.com
 
7CardBud

7CardBud

Well-Known Member
Billy the Mountain said:
It's probably fine for hydro in a pinch, but I've avoided hydrochloric acid because of the chloride. I haven't done the math the calculate Cl- ppm at typical pH-down concentrations. Cl is a micro-nutrient (at a few ppb) but is toxic to plants at higher levels, a mere 20 ppm is harmful.
I do concur it's amazingly effective removing hard-water stains.

A short article on chlorides and hydro:

What is the effect of chloride in hydroponics? – Science in Hydroponics

scienceinhydroponics.com scienceinhydroponics.com
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Another reason I have found Athena suspect, their Fade is CaCl2 and it is used in rather large quantities.

I figured since HCl was so strong it would add acceptable amounts of chloride to a solution. If I get bored I might crunch the numbers next time
I mix a rez.
 
curious2garden

curious2garden

Well-Known Mod
Staff member
Drop That Sound said:
On the other hand, not knowing exactly why pH UP/DOWN is blue and orange is all the more reason to DIY your own, and know exactly whats going into your mix. It seems more cloudy like tampico orange juice than really clear like hi-c or orange koolaid though. Thicker. More like they are using a powdered substance as the dye..

Either way, I will probably go ahead and add a few drops of food coloring and call it good ;)
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Never gave it much thought other than it being a color indictor so you didn't grab the wrong one. If you think about pH color indicators blue/purple denotes alkaline and red/orange acidic.
1726805802547.png

The one thing AN I use is their pH down. It's clear LOL
 
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