I would have thought that any acid with a low enough pka would be capable of transforming carbonate to bicarbonate and eventually to CO2. It would be similar to the way vinegar (usually a 5% solution of acetic acid) dissolves the calcium carbonate in egg shells.
What we thought too until a chemist told us otherwise. This happened on Garden Web way back when. If you use vinegar you will have to use more each time. The acid is destroyed by bacteria and the chemical reaction creates a carbonate as the calcium is freed. The chemist wrote out the equation and confirmed the freeing of carbonates. Dissolving the egg shell will end up increasing pH once the vinegar is destroyed by bacteria. I would think pH would increase as the calcium is now free not locked up in the shell material molecular matrix which takes a long time to break down.
All acids will dissolve egg shells. Carbonates bond readily with them. Again the problem is what happens long term? With vinegar it removed the carbonates for 2-3 weeks and then it is released. With sulfuric acid the calcium and sulfur combine the acid is destroyed and so is the carbonate
I might try this with egg shells that go into the compost.They take a long time to break down otherwise.
I wanted to note that if we are talking about growing blueberries in containers vinegar can work. Because you can flush out the calcium as it is soluble now. Not so much though in raised beds. Nowhere to flush it out to.
So the microbiologists say that calcium acetate is metabolized to calcium carbonate? Who knewā¦
Itās not uncommon for reactions to go either way, Calcium acetate is also known as acetate of lime.
Itās your typical acid and a base make a salt and water equation
This study states exactly what you said. Acetate to carbonate by bacteria, believe it or not. Note bulletin point 3
https://www.jstor.org/stable/pdf/24520986.pdf
There you go clear as day! Itās good to question things, you made me have to prove it. Which I just did.
Iā m starting to like you 
As I question everything too. I love Farmers Fredās rules of gardening, One is everything you know is wrong. Another is Mother Nature bats last.(which applies here).
Thanks for pointing out my background too, technically Iām a Medical Technologist but I have about 70 credits in microbiology. My degree is a BS in Medical Technology from college of Human Medicine at Michigan State University. The microbiology department asked me to change majors as I happen to be an excellent microbiologist, but I knew I could get a higher paying job as a med tech in any hospital. I also worked for the anatomy department at MSU as a lab tech in their cancer studiesā¦ I worked mostly at Sparrow Hospital in Lansing MI.It was fun as the HIV virus just was discovered and I had a chance to work with that virus. We were trying to find a good media it would grow in, but someone else beat us to it. Still I enjoy doing bacterial, fungal, and viral research which was my specialty.
I understand though, when you find out what you have been doing is completely wrong. Fredās rule of everything you know is wrong applies, I didnāt realize this reaction occurs until a chemist pointed it out when we were discussing this on the Garden Web forum years back. He was correct! I always hated chemistry even though I have 15 credits in organic chemistry and 7 credits in Biochemistry it was never my forte.
Mother Nature bats last! That is a great one and applies to most of my career. I hope you donāt mind if I use that.
All of this discussion around microbe metabolism of carboxylic acids (acetic acid in particular) peaks my interest. It is amazing that some of the good basic work done in this area is more than a century old. The Kellerman and Smith reference that you pulled up is pretty much pre-WWI. I poked about a tiny bit and found a 50 year old study in which they used radio-labelled carbon to track some of the metabolic pathways of acetate in soil. Half of the carbon-14 labelled acetate was labeled at each of the two carbons (carboxyl and methyl) in the acetate ion. They tracked over a period of 200 days the radio-carbon in 5 types of material: carbon dioxide, mineral carbonate, amino acid, carbohydrate and other, unidentified insoluble material. If I read figure 1 correctly, after ~ 2 weeks approximately 20% of the radio carbon appeared as carbonate. If one considers the perhaps plausible scenario that all of the carbonate is derived from the already highly oxidized carboxyl carbon in the acetate then ~ 40% of the acetic acid molecules would be generating carbonate. That is pretty cool! If not for your posts and this fine forum I would never have learned that. Perhaps a good rule of thumb to keep in mind would be - always consider what the microbes are doing which for me translates to- ask a microbiologist.
Sorensen and Paul; Transformation of acetate carbon into carbohydrate and amino acid metabolites during decomposition in soil
When I was a little kid I used to do that trick with eggs and then take the ārubberā egg in for show-and-tell. It was cool even before youtube. 
Heh, I like #10 āBermuda Grass Is Foreverā
great way to make hard boiled eggs you dont have to peel. 
Another data point on acid for blueberries. I just got some Citric Acid today to use in combination with the commercial PH Down (Phosphoric Acid) for use with my miracle fruit and blueberries. $16/5 lbs on ebay.
I use Reverse Osmosis purified water adjusted to 21 ppm with aged tap water (18 ppm for miracle fruit). 1/8 tsp USP grade Citric Acid reduces 5 gallons of water to circa PH 4. When this is mixed 50/50 with 21 ppm water PH results are a little over 4.5. Overkill for Blueberries but if youāre looking for an acid bathā¦
In another test, I added 1/8 tsp Citric Acid to one gallon of 18ppm water and 6 parts 21ppm to one part of the acid mix to get over 4.5 PH at this rate $16 Citric Acid will treat over 4400 gallons of water for miracle fruit. For Blueberries, more water could be treated (5.0 PH). Not as much as the 950 ml 98% sulfuric I got for $18 (for scarification), true but a lot less hassle.
I recently bought a commercial garden soil probe PH tester and checked it against my Hana and a cheap Chinese lab tester. You can have the soil tester for the cost of shipping.
I have noticed a strange phenomenon when I acidify my water.
Fill a watering can with 2 gallons of water and add a small amount sulfuric acid.
Measure the PH with the cheap Chinese PH meter. It will read 4.0
Come back in an hour and the cheap meter reads 5.0
I wonder if the water needs a lot of time for all chemical reactions to finish before getting a stable ph. If I use the fresh mix at 4.0 ph will it burn the roots and then get neutralized by the base in the soil and water, causing more harm than good? If I make the fresh mix ph 5 it seems like it will not really acidify the soil.
Also I found sulfuric acid drain cleaner at the hardware store, When you pour it into a bucket of water it makes a hissing sound. I cant believe they sell this to idiots like me.
Is the meter a probe type?
A pH of 4 isnāt super low for Blueberries,but if the meter isnāt very accurate and the real reading is around 3,there could be trouble.
I advise either getting test strips or solution for measuring.
When you say adjusted to 21 ppm you mean 21 ppm of what?
If you are lowering the pH without a buffer then even sneezing in the general direction of the mixture will likely move the pH by a full point. This is a common problem in aquariums. If you use RO water it takes very little to change the pH by a huge amount, but it also takes very little to move it back.
TDS meters actually use EC and convert using standard formula so technically when I state TDS in PPM its not of a particular component but rather the EC equivalent as reported by a HM Digital AP-1 TDS meter. Total dissolved solids - Wikipedia
Tap water here reads about 220 PPM, rain water on the West Coast is about 21 PPM. My RO filter unit produces water with a reading of 7Ā± depending on temp and pressure. Water that reads anywhere near 7 PPM is too pure and will damage roots if applied direct (my orchids have exposed roots) so I add some aged tap water back until I get to a reading of 21 PPM.
As @PA_Fruit_Grower stated in response to @cowardly_lying very pure water has near no buffering ability at all. It is the impurities that provide any buffer effect.
Sounds like you are using unpurified tap water @cowardly_lying . For 2 gal it shouldnāt take an hour but thorough mixing and 20+ min seems reasonable. My Chinese meter needs to be calibrated every session, itās still as much as 0.5 ph off from my Hana after a reading or two. My Hana gets calibrated with 2 buffer points every few sessions or when Iām calculating new mixes. Do you rinse your probe in RO/Distilled water between readings and keep it in storage solution? How long after dipping meter in solution do you wait to get a stable reading?
I would not water plants when meter reads not reasonable to do so. Wait until things settle out.
As @PA_Fruit_Grower mentioned very pure water has near zero buffering ability and you would not see such a change with H2SO4.
Thanks muchā¦ It seems then that it is a total dissolved solids measurement based on conductivity and the assumptions (1) that the conductivity is mostly due to inorganic salts and (2) that the relationship between dissolved inorganic solids and their ionic conductivity is fairly constant everywhere. cool Iāll buy that.
Itās not perfect and there is a fair amount of variability in true EC-TDS conversion but itās the only cost-effective tool for indications of concentrations. EC is a huge factor in biochem systems and solutions with high enough EC will damage roots, the level being dependent on the sensitivity of the plant.
PH does not seem like a very useful measure. In electricity voltage is the potential difference and amperage is the capacity. Wattage is the useful measure of power. Is there a wattage value to acidity?
Putting a drop of sulfuric acid into a gallon of distilled water would move the PH a lot. I wish there was a way to make water have a PH of 5 and enough capacity to not be instantly neutralized by the soil?