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Using peat to lower water PH?

Posted by spaceman13 6b (My Page) on
Sat, Jul 14, 12 at 11:07

I have hard water with a pH of about 8. It hasn't rained much lately so I've been watering with a lot of my nasty tap water.

Years back I used to have Discus fish and they require soft, acidic water, which I collected in 6 gallon jugs from a roadside runoff drain. The water was perfect, and going to get it was a beautiful Sunday morning drive in the woods. That was when gas was about buck a gallon, or less. Today's gas prices, and my poor fuel mileage, and lack of time prevent that at present.

One method of conditioning water (which I never used) was by filtering it through peat. A container was set up and filled with water. A pump recirculated the water from over the peat substrate until the desired pH was attained.

I heard of using vinegar to lower the ph, but I've also used vinegar to kill weeds and a few tree stumps.

It makes me wonder if peat filtration would be a better solution.....or am I missing some tid-bit of biological wisdom that would render this harmful to my plants.

Any thoughts?


Follow-Up Postings:

RE: Using peat to lower water PH?

You could. The brown color of peat-filtered water comes from tannic acids. In large amounts, these are thought to be phytotoxic. Since peat is such a common ingredient in container mixes, it's unlikely this is a serious issue.

But it would be much easier and more accurate to use vinegar (acetic acid), citric acid, or phosphoric acid. There are many threads about thiw on gardenweb.

Yes, vinegar can act as an herbicide when concentrated. But that's thing, it's all about concentration. If you're using it to reduce your water pH to something good for your plants, you'll be using a very small amount (1-2 oz per gallon is normal). In addition, it's likely that organic acids like the acetic acid that defines vinegar, and the citric acid that can be found online or in Asian grocery stores, has secondary benefits to plants by chelating and extracting micronutrients from the soil. These same organic acids are exactly the chemicals secreted by plant roots to capture certain nutrients.

So yeah, I wouldn't bother with the peat. Have you considered how messy that would be? On a side note, blackwater rivers, including those that drain peat bogs, get their dark color from these same tannic acids.

RE: Using peat to lower water PH?

Excellent info greentiger.
I'll assume that too much tannic acid could be as potentially harmful as using too much vinegar.

I read (or skimmed) a few of those treatises, I was not aware about the micro nutrient chileating effect of vinegar, good to know.

The black water rivers get it due to the amount of leaf litter that falls into, and accumulates in the very slow moving water, and yes, peat filtration can get very messy. I never did it, but have seen it done. Nit to mention that I no longer have all the necessary components to set one up.

It guess this fits well with one of my philosophies of life,
"Everything is good for you, everything is bad for you.
It all depends on timing and dosage."


RE: Using peat to lower water PH?

  • Posted by nil13 z21 Mount Washington (My Page) on
    Sat, Jul 14, 12 at 18:15

These days, i think most discus keepers use Reverse Osmosis because peat is such a PITA.

RE: Using peat to lower water PH?

I used to use peat to lower the pH of my discus tanks when I kept them. I had a 20 gallon tank set up that I would filter with a canister filter loaded with peat. En I would use that for my water was definetly a PITA lol. On my gardens, I use a hose end sprayer with white vinegar, it seems to work pretty well. I also used an inexpensive GE filter housing with a carbon cartridge and garden hose inlet and outlet adapters to strip out the chlorine in my tap. Probably not needed, but I do it anyway. It was only about 30 bucks to make the filter.

RE: Using peat to lower water PH?

howelbama, My friend used a garbage can and a submersible power head and a cheesecloth bag. Total PITA!

Nice idea about using the hose end sprayer with the white vinegar! I would never have thought of that.

I think I an just going to bite the bullet and get a rain barrel setup.

RE: Using peat to lower water PH?

The only reason vinegar is toxic to plants in it's grocery store concentration is the pH, which can be as low as 2.4. If you use vinegar to lower pH to a healthy range, it will have no ill effects.

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