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Using sulfuric acid (33% pure) for ph down?

Discussion in 'Hydroponics / Aeroponics' started by Valron, Jan 23, 2012.


    Valron Well-Known Member

    Question on ph management...

    I have recently read that you can use pure 33% sulfuric acid from auto zone to lower ph.

    Well I tried it . It works it's safe and for the price of 1 u.s. Gallon of ph down is under 5$.

    Only negative aide effect? I can't read the tds. My ppm meter goes CRAZY!.

    Any suggestions?

    Oh yeah i am putting this stuff right into my 18 gallon resivior...


    Justin00 Active Member

    while i can attest that adding a 33% solution of sulfuric acid to you res will in fact lower you ph, i cannot say what adverse effects it may have on your plants health.

    cannabineer Ursus marijanus

    How many drops does it take?
    What pH and tds meter are you using? cn

    ^Slanty Active Member

    My suggestion, go support your local grow shop and by the proper solution so you CAN read your TDS meter!

    CanniCastro420 Member

    You can use it, but you are supposed to dilute using distilled water. Get a gallon of distilled water. Dump out 1 -1 1/2 cups of the water and replace with sulfuric acid. I'm currently using it to lower the ph on my 2 mother plants I'm working on. And to be honest, the ph is more stable. Its totally safe to use. Berry farmers use the same stuff to lower soil ph.

    Valron Well-Known Member

    Hey canna I'm using about 15-20ml of the distiller water/acid mixture to lower the ph from tap base.

    I use general hydroponics testing solution for my ph testing

    And I got a free tds meter when I bought a 5$ water purifier.(maxes at 999)

    After cleaning my resivior and re-phing using the sulfuric acid solution it never messed with my tds!

    And also like the other poster advised... It's WAY more stable than vinegar or lemon juice.

    And there is no way I am spending 40$ on a gallon of ph down when I can make 4 gallons for about 7$...

    EDIT: ZERO pest issues with this product opposed to lemon juice and vinegar!!!

    JohnnyGreenfingers Well-Known Member

    This. /thread

    mike91sr Well-Known Member

    Sulfuric acid is a better alternative (more stable, less residue) to the phosphoric acid used in most pH Down products. Just because GH doesn't package it and slap a huge price sticker on it, you'll find little support for it on this website though. I wouldn't recommend using 33% though, it's the diluting and stabilizing ingredients that can cause problems; I use 98%. 1L is $15 on amazon, I mix 1gal of water with 1 tbsp h2so4, it's just as strong than the $30 bottle from GH. Everyone here can do the math. pH products for hydro are one of the biggest scams I've seen in the industry.

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