What do you use to acidify your water?

Ok, been reading about alkaline water as that is what I have. I purchased Up/Down to get the right PH, but it appears I will mostly, if not always, be acidifying my water. Up/Down uses phosphoric acid, citric acid, and ammonium phosphate. It appears phosphoric acid can add to a phosphorus build-up since phosphorus is also used in fertilizer. Further, it appears ammonium phosphate can mess-up fertilizer. According to my research, citric acid is the most benign. So, I am considering switching to citric acid exclusively to acidify my water.

What do you use? Anybody have any thoughts?


pH is measured on a scale from 1.0 to 14.0. Pure water has a pH of 7.0 and is considered pH neutral. pH below 7.0 is considered to be acidic and pH higher than 7.0 is considered to be alkaline.

A substance that decreases pH (pH-down) is called an acid while a substance that increases pH (pH-up) is called a base. A substance that helps nutrient solutions resist pH changes when an acid or base is added, is called a buffer.

A pH difference of 1.0 is equal to a ten times increase or decrease in pH. That is, a nutrient solution with a pH of 6.0 is ten times as acidic as a nutrient solution with a pH of 7.0. A pH difference of 2.0 is equal to a hundred times increase or decrease in pH.

It is very important to keep the pH level within certain limits when growing marijuana. Even first time marijuana growers need to monitor the pH of their nutrient solution or soil and keep it within optimum levels.

So here at the bottom is a list of some buffers that are good to go with when raising and lowering ph!

Here are some ph buffers when your ph is too high: Use these SOIL PH Adjustments to lower your ph: sawdust, composted leaves, wood chips, cottonseed meal, leaf mold and peat moss. Sawdust, composted leaves, woodchips and, lemon juice, PH DOWN.

Hydro PH Adjustments: PH Down (vinegar and lemon juices are good for soil, but not recommended for hydro use) Phosphoric acid during flowering and Nitric acid for vegtative growth.Thanks goes out to syko2 for that one! (Only quality PH buffers should be used to adjust ph and be sure the buffer and nutrient work’s well together.)

Here are some that will raise the ph: use these SOIL Adjustments when your ph is to low: PH UP, dolomite lime, hardwood ash, bone meal, crushed marble, or crushed oyster shells, potassium hydroxide <— Thank you Uncle Ben!

Hydro Adjustments: PH UP,lime,potassium hydroxide and potassium sillicate .(Only quality PH buffers should be used to adjust ph and be sure the buffer and nutrient work’s well together.)



I have and use citric acid. A little goes an incredibly long way. No issues.

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What about white distilled vinegar for PH reduction?

Are you growing in soil, soilless, hydro, aero, etc? The amount of phosphorous added to the system by straight phosphoric acid is negligible. I recommend buying a small container of full strength acid and cutting it with distilled water to easily adjust small batches (under five gallons of nutrient solution, even a few drops of straight acid can cause a very large change in PH.)

Just realized this topic is a month old…

@Openmind try starting a new topic next time.

You can use small amounts of vinegar if you’re growing in soil.

what ratio of citric acid (lemon juice?) to water did you use.
my pH is 7.0 and I’m aiming for 6.5 in homegrown soil/compost/perlite and sunshine …thanks in advance…:face_with_monocle:

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The stuff is really powerful. But it will vary depending on the solids in your water. The only way to administer the correct amount is to measure using a good PH meter.

I have a BlueLab pH meter and pure Welsh water@7 pH from the tap.

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