dear zachman,
looking at previous threads on the topic is helpful:

If anyone else is wondering about this topic, or wants to talk about their experience with limestone in their mix, please do. however, i think i answered my own question here. I should have researched before i posted. oops.

-zachman

Here is a link that might be useful: helpful

I wouldn't add any limestone to a mix like yours. Peat-based mixes tend to be overly acidic, but your mix will be much closer to neutral. Since most plants prefer slightly acidic conditions, your mix should be fine as is.

But there is also the consideration of tap water. Many water supplies are quite alkaline. My own tap water is very high in calcium carbonate, and has a pH over 8. So I'm basically watering with liquid limestone. I actually inject acid into my water to neutralize the alkalinity, and lower the pH. There's been some discussion on this board about adding vinegar or other acids when watering succulents and other plants.

I doubt a 10% addition of limestone will make or break your growing ability, but my guess is it will do more harm than good.

Yes, it is more effective to add fine powdered Dolomitic Garden Lime to your bark-based mix.
I believe the rate is 1 teaspoon to 1 gallon of mix.

If you want to get fancy, test the pH of the water that runs out of your container soil.
A pH of 5.5 is just fine for container media.

As Penfold mentioned, test the pH of your tap-water.
Start adding a teaspoon of acid - like white vinegar - until you bring the pH down to an acceptable level.
Then, whenever you water, simply add this same amount of vinegar (or other acid).

My tap-water is fairly neutral, so I only occasionally add a capful of white vinegar to a gallon of water
for my maples, conifers, and citrus.

Josh