If egg shells are in short supply (or lime), then you could try antacid tables with vinegar, but check that these tables contain calcium carbonate and
not other metals like (sodium, potassium, aluminium or magnesium) which are sometimes used in antacid tablets.
The reaction of antacids tablets (calcium carbonate) and vinegar (acetic acid in water) produces calcium acetate and bubbles (of carbon dioxide). When no more calcium carbonate remains, the reaction will stop and so no more bubbles will be produced. Therefore the lack of bubbles will let you know when the reaction is over. Also at the end of the reaction the vinegar taste should also have disappeared.
Therefore, you could by adding antacid tablets (best crushed) to cheap white spirit vinegar to get calcium acetate.
Therefore, if I was doing this reaction I would use the following method:
- Step 1: Pour the vinegar (e.g. 100 mls) into an open container like a Pyrex jug. Do *not* use a sealable container!
- Step 2: Add 5 to 6 crushed antacid tables to the container, stir, and leave over night (I repeat do ***NOT*** seal this container, as the gas (carbon dioxide) produced would probably cause a sealed vessel to crack or even
explode , due to too much pressure being trapped inside the sealed vessel!!!! (i.e. like a ballon which has been blown up too far)) – keep a record of tablets added.
- Step 3: Sniff the container in the morning. If it still smells like vinegar repeat Step 2, but maybe using fewer antacid tablets (e.g. 2 or 3).
- Step 4: If the solution no longer smells like vinegar, dip your finger in and taste a little. If it taste sour repeat step 2 (again perhaps using fewer antacid tables).
- Step 5: It is probably best not to add more antacid tablets than needed to neutralise the acid, as calcium carbonate is a little basic. Therefore too much calcium carbonate might cause your soil's pH to rise. If you are worried that there is too much vinegar left in solution you could allow the solution to evaporate – acetic acid will evaporate over time. Too much acetic acid will lower your soil's pH.
- Step 6: Once you know the ratio of antacid tablets needed to neutralise the volume of vinegar used, you can repeat this process when ever you need to (as long as you use the same brands of antacid and vinegar!)
I've had a quick look at Thaichillihead numbers mentioned above, and they seem about right.
I've also had a look at approximate number of antacid tablets needed to neutralise vinegar. The problem is that vinegar seems to be sold in different concentrations
i.e. from about 5% to 15% acetic acid in water.
Therefore based on the antacid tablets containing 500 mg of calcium carbonate per tablet, you would need:
:: About 17 (500 mg) antacid tables for 100 ml of vinegar (when the vinegar contains
5% acetic acid), giving about 13 g of calcium acetate.
:: About 27 (500 mg) antacid tables for 100 ml of vinegar (when the vinegar contains
8% acetic acid). giving about 21 g of calcium acetate.
:: About 33 (500 mg) antacid tables for 100 ml of vinegar (when the vinegar contains
10% acetic acid). giving about 26 g of calcium acetate.
:: About 40 (500 mg) antacid tables for 100 ml of vinegar (when the vinegar contains
12% acetic acid). giving about 32 g of calcium acetate.
:: About 50 (500 mg) antacid tables for 100 ml of vinegar (when the vinegar contains
15% acetic acid). giving about 40g of calcium acetate.
A quick search indicates that Foli-Cal is a 10% solution of calcium acetate (maybe has other good stuff in it too?). In that case 1L of Foli-cla would contain about 100 g of calcium acetate.
Therefore, using about 125 (500 mg) antacid tablets with 750 ml (5%) vinegar, topped up to 1 litre would give you about the same concentration of calcium acetate as is in Foli-Cal. I think making your own solution from antacid tablets and vinegar would cost about 5 bucks ??
Based on the above numbers, making calcium acetate from antacid and vinegar seems more cost effective than buying Foli-Cal …
The only problem I can see is that the antacid tablets might contain other stuff like flavours etc ...
