Using calcium carbonate to control acidity

Sep 10, 2005 4 Replies

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<salmonegg 20 years ago

I do a lot of hobby hydroponic growing. I have noticed acidity building up in some of my pots. I attribute it to the preferential consuming of potassium that leaves the nutrient solution more acid.

Today, I bought some marble chips. I placed a handful in several of my nutrient containers. My expectation is that as the solution becomes more acid, the marble will decompose giving of carbon dioxide and thereby consuming some of the acid. I will report on whether this keeps the pH above

6.0.

Has anyone had experience with this kind of pH control?

Bill

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Dwayne 20 years ago

My problem has always been getting the pH to go down, not up.

Dwayne

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<salmonegg 20 years ago

Although I have not had a long observation time, my pH is hovering close to

6.0.

When you say you are having trouble getting your pH down, are you talking hydroponics or soil?

Bill

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Dwayne 20 years ago

Soil. My blueberries died here and the blackberries werent sweet and had no flavor. Blueberries require a pH of around 4.5 and we have 6.9 here. I was told that the only thing that will grow in a pH above about 8.8 is weeds.

Dwayne

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<salmonegg 20 years ago

I am using the calcium carbonate (marble) for hydroponic pH control.

For your problem, you might want to consider using Gypsite. It is combination of gypsum and sulfur. You can also try sulfur by itself. Also, you can use ammonium sulfate or nitrate. That should acidify the soil quickly. They are combinations of a weak base and strong acid.

Good luck

Bill

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