pH Down Acids - Sulfuric vs Phosphoric vs Citric vs Vinegar

Need a little help here. I have a problem with my pH being too high due to my well water. I am growing in FF Happy Frog. I’ve been reading about using sulfuric acid, phosphoric acid, citric acid and vinegar to bring pH down. I know General Hydro pH down contains phosphoric acid and FF Cultivation Nation pH down contains citric acid.Some people use sulfric acid ( battery acid), while others use phosphoric acid (Miracle Sealants Phosphoric Acid Cleaner( at Lowes) concrete cleaner- is this safe to use?). People say make sure the phosphoric acid is food grade, but they don’t say that about the sulfuric acid. It seems that citric acid or vinegar would be safer. Would like to have input from people that have actually used these materials in soil, (not just read about them, like me). Also some info about how to use in soil (Happy Frog). Info on how to apply, how often, how to mix or dilute, what to avoid, what to watch out for, etc. Should I use to mix when adding nutrient solution, or when just watering, etc. Any info from people who have actually used these acids and their results and experiences would be greatly appreciated. Thanks.

OP here…topic title should have been " pH Down Acids"…Forum won’t let me correct, sorry!


I use Phosphoric Acid… They sell that as a PH down solution in my area, just not branded…

I got it for you.

Thanks, oldmarine!

Gosh, I thought I’d get more responses than this! I had hoped someone had tried these remedies and could give me some pointers. Am I posting in the wrong area? Surely someone has some answers to my questions.

I personally would stick to Phosphoric acid as it’s a micronutrient. No idea of any food grade sulfuric, citric IME takes way more and vinegar can take a lot as well to make a change in PH. If doing purely organic I’d go with vinegar but really that would be the only reason.

I like and use the GH and Botanicare product. The FF seems to take a lot to effect a change.

I use citric acid - $4 in the baking aisle. Just takes a tiny pinch and a bottle will last through 100’s of grows.

The pH of my feed water runs in the mid to high 7’s. If yours is higher than that maybe another acid would be better.

Lemon juice is a good ph down and so is coffee believe it or not and the coffee is a good food for ur plants aswell

Thanks everyone for the info, hopefully one of these remedies will do the trick!

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i’ve used citric in a pinch but normally stick to the orange jug of ph down. I found when i was mixing for 3 days at a time the citric didnt hold ph as well as the Ph down(orange stuff)

I went to the pH up and pH down with the rest of the crowd long ago as it’s simple

Anybody got any recommendations on a digital pH meter? One that you’ve used that is accurate, reliable, and inexpensive? I have one of those 2 prong analog jobs, but it never reads the same twice…don’t trust it.

I use white vinegar. Just a few drops in a 2 gallon bucket gets me from mid 7s to about 6.5ish.