pH-alteration (downward) - what acids do you use, if any?

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pH-alteration (downward) - what acids do you use, if any?

Postby Iheartbougs » May 13th, 2018, 8:27 am

I've got the un-lucky circumstance of 8.0pH tap-water, so while I'm in the process of refining my rain-barrel setup (which is ~4.7pH in my area) I'm approaching the pH-problem with acids.

Phosphoric acid seems to be the ultimate go-to for this (General Hydroponics' "pH-Down" product is ~75/25% phosphoric/citric acids, for instance; botanicare's is pure phos.acid), however most of my specimen are bougies that are about as 'in-development' as can be, I love flowers like everyone else but am trying to push vegetative growth and really don't want that heavy phosphorous load that I'd get in trying to use phos.acid to bring 8pH water to 5.5pH....will be flowering out of control.

Muriatic(hydrochloric) seems OK but leaves chlorine which can accumulate....nitric seems best, though dangerous to get and work with - however, I recently found that sulfuric acid - aka, battery acid - was in-use amongst hydroponics gardeners w/ success, and I don't mind a higher Su load (compared to Phos!)

My problem is two-fold here - I've yet to find *any* way to actually use the product (ie how much to use to get the pH to X), as well as any 'final word' on what specific things to be sure of - people seem to say "just go to an auto parts store and get battery acid" but, frankly, I fear by-products/additives, am not really expecting generic battery acid to be some lab-grade sulfuric acid yknow?

Thanks for any thoughts on this one! I only found out my pH problem recently, had a bad chlorosis problem I couldn't get rid of no matter how much iron I threw at it, and finally found that it was basically pointless because at 8pH iron is virtually un-absorbable!
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Re: pH-alteration (downward) - what acids do you use, if any?

Postby treeman » May 13th, 2018, 11:28 am

I used to use oxalic, citric and sulphuric. Sulphuric is dangerous so be careful. I think it's the best though. If worse comes to worst use pure vinegar.
Don't use hydrochloric.
Another alternative is to sprinkle agricultural sulphur on the mix. I need to look up my books for quantities......
Last edited by treeman on May 13th, 2018, 11:30 am, edited 1 time in total.
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