How to change the ph from 7.5 to 6.5?

Please let help I have a basic understanding of ph chemistry. Hi do you safely change a 2 gal container to more acidic?

You simply need to use some pH down. But, buy both the “up” and “down” products, as you will eventually need both.

They can be found by clicking here.

And - welcome to ILGM!

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Go to Walmart and buy some citric acid!
$4 buck goes a very long way and it’s natural not chemical!
Depending on what your starting Ph is will determine how much is needed, when I was using my tap water at 8.6Ph it took less than an 1/8 tsp per gallon to lower it to Ph 6.8
Up to you natural or chemical adjusters

Hope this helps and HAGD

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Is the citric acid powder or liquid? Any harm in using natural lemon juice?

Phosphoric acid is the best and has pH buffering at the 5-7 range, but citric acid or acetic acid(vinegar) can work as pH down. What you need is greater buffering capacity/strength at the pH desired to maintain the pH in the soil, so it is best to have nutes containing phosphates that is properly pH’d to 6.5 that is run through the soil. Simply adding pH’d water will not bring down and hold the pH in the soil effectively.


Vinegar pH down and. Baking soda pH up!!

Baking soda will work, but is released as CO2 (bicarbonate) so it is not an effective buffer, but it will bring the pH up. A better pH up would be potassium hydroxide (KOH)

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Gotta be careful with this but if you know how to use it then the plant able to actually convert citrates to phosphates and use that as energy.

This is known as the Krebs Cycle

Be careful here also. Calcium carbonates and calcium bicarbonate are good for plants in the right doses but baking soda is sodium bicarbonate, which is not good for plants at all. The sodium part of the chemical will burn the plants.

It is crystal / powder form
This is about how much I would use to lower Ph 2 points in a gallon of water.

I’ve only went through about 1/3 of a 5 Oz container during my first grow.

People do use lemons to lower Ph too.
Not sure if the cost would be reasonable nor how many lemons it would take etc.

Hope this helps and HAGD

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@TDubWilly kreb cycle conversion of sugars to energy…does not generate phosphates


Differnce between calcium carbonate (antacid) and sodium carbonate (baking soda) is simply the counter ion Ca vs Na


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If your growing with chemical nutes then that will be an issue but if your growing using natural nutes then the little critters in the living soil will handle the Ph and it is common for the soil Ph to have different Ph based on water saturation and depth and so on.
Live soil Ph is handled by the critters. If you decide to use chemical nutes all bets are off as you kill the critters so they won’t do what they do best and feed your plants


Lemon juice also contains sugars although minimal


Nevertheless, sodium will burn plants many times quicker than any ph up or down products

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@TDubWilly I agree. Calcium is more useful for calcium pumps on the cell membrane (larger molecule transfer), but Na is also useful for sodium channels for transfer of solutes into the cell.

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WickedAle hit on the head with H3PO4, plant foods are formulated to be slightly under on phosphorous to avoid toxic buildup, using Phosphoric acid (human grade) helps replenish P.

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The problem of using citrate and acetate is that it is consumed by the above kreb cycle and doesn’t buffer to keep the pH where it is. It is only transient in its pH affect.

They are very short acting yes.

As far as sodium bicarbonates, that’s your call if you wanna use it or not. I personally would never use it to adjust my pH because the pros are far outweighed by the cons in my opinion, especially when the proper adjusting chemicals are so cheap.

A box of arm and hammer is barely less than a bottle of something designed to alter pH

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Neither calcium or sodium carbonate is useful for pH because it is also transient as CO2 gets released. Best to use (KOH) potassium hydroxide or calcium hydroxide(lime), alternatively sodium hydroxide (threw that one in for ya @TDubWilly ):clown_face:

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Citric acid granules are excellent! They work well with your soil food web. Phosphoric acid is great, too, but it will kill your microbes. Filtered cider or white vinegar works in a pinch.

Potassium bicarbonate granules work well as an organic pH up. By organic, I mean it plays nicely with your microbes.