Sometimes it is better to grow what grows there instead of using chemicals to change the environment.

Ammonium sulfate is the fertilizer of choice for blueberries and, along with appropriate soil amendments, may be able to remedy the situation.

It's worth the money to have professional soil test done and to request recommendations for growing blueberries.

Are you in the US?

If so, most likely your county's Extension Service office has info for growing blueberries in your region. They'll also tell you if it's an impossible task.

To locate that office, use this interactive map:

http://npic.orst.edu/pest/countyext.htm

I think the MColorpHast pH 4.0-7.0 that I've used are worth the cost. Rainwater is best for sure. If you use ammonium sulfate, AS, regularly with rainwater it's possible to get the pH too low. Same with battery acid and well water. So don't go over board with any of the strong acidifiers. I know that from firsthand experience. Don't lower pH of well water below 5 esp if using ammonium sulfate with that. You could probably get by using well water and AS. The AS could be enough to counteract carbonates in the well/municipal water.

AS added to water won't show up as being acidic right off. The bacteria need to convert the AS in the soil in order to affect pH. But they will and if used once a week your media may be too acidic in a few months.

fruitnut, I don't have well water. If I understand you correctly, mixing 0.5 tsp of AS with a gallon of tap water should be good enough to neutralize the carbonates? Does that happen inside the soil when the sulfate becomes available? Should I perhaps lower the ph of tap water to around 6 before mixing with AS just to be sure that the carbonates will be neutralized? My knowledge in chemistry is very poor...

You say rainwater is best for blueberry plants, but are there any other reasons why tap water is not recommended besides having a high ph and the carbonate issue?

The AS is broken down in the soil. That's when pH is lowered. That should happen in a week or two so would be continuous if applied every week.

The amount of AS needed to counteract the carbonates in municipal water will vary because that water varies in carbonate content. You could try pH 6 and see how it goes. At least that would take out most carbonates.

Plants can look similar with pH too high and pH too low at least initially. Both start with chlorotic looking leaves. If the leaves start showing gray dead streaks that's too low.

Nothing easy about this when you are dealing with carbonate loaded water.

When you get a professional lab test, they take into account local factors, including carbonate loaded water, when they make recommendations.

Thanks fruitnut and Jean.

According to my city's annual analysis report, calcium makes up 12 mg/l (raw water) and 18 mg/l (distributed water)

For magnesium, it's 3.0 mg/l (raw water) and 2.8 mg/l (distributed water)

pH: 7.3 (raw water) and 7.5 (distributed water)

No clue what's the difference between raw water and distributed water, but I'm assuming it's the numbers for distributed water that I have to consider.

So with these numbers, would it be possible to know exactly how much sulfur is required to eliminate the carbonates?

I have sulfuric acid (precisely 9.6%) in a droplet bottle. How many droplets of 9.6% sulfuric acid is needed to eliminate the carbonates in one liter of tap water?