Help with Rocks

[pugoff]

HI guys.

I am a newbee this site, and have been browsing the forum, and getting some amazing ideas. This is where I need some advice,

I went out today for a wander, and remembered about an old, disused quarry local to me. I went for a look and found, what i believe to be slate, in rock form.

I found a good amount of it, so decided to take it home and scrub it up. I have not yet boiled it, just rinsed off the dirt and gave it a quick scrub. I then, for some unknown reason, decided to test it. Good old vinegar test, and me it fizzes.

Its not a big fizz, just a small almost hiss that I can hear, I can not see any bubbles on it anywhere. These stones have been outside a good few years. Is the fizzing likely to be the crap that has grown on it over the years?
Should I boil it and test again, chuck it, risk it?

What do you guys recommend?

 

[Danny]

It will be a Calcium reaction that's all,as long as you do not mind it buffing up your ph & kh just scrub and use.

 

[pugoff]

How much is it likely to buffer my PH & KH?

I am going down the shrimp route again, and know they like low ish PH & KH

 

[Danny]

Depends how much rock, water volume, just how much of what ever buffering mineral it contains ( lime, calcium etc )

But I would guess not above 8 / 8.4max which would be fine for Neo's from what I have read.