Rock collecting

So I'm wanting to find some rocks for my new aquarium and I read that if you can etch them with a steel knife ( hardness:7) they're too soft and they'll slowly dissolve in your water, making the hardness go up. I've found a rock that I really want and it only scratches minutely. Is this fine or should I put it back?

 

Do the "vinegar test". Place a drop of vinegar on the stone. If it fizzes, it will raise your pH and hardness.

 

The only way to be completely sure, is to put it in a bucket of water for two weeks, then test the water.
But yes if the viniger fizzes, it will probobly effect the ph. however, not all rock that effects ph will cause the fizz and i would not doubt that it is the same with scratching the rock.

 

What are your fish? rocks that raise pH and hardness are beneficial for most livebearers and african cichlids. Something from like the amazon its not recommended.

 

What are your fish? rocks that raise pH and hardness are beneficial for most livebearers and african cichlids. Something from like the amazon its not recommended.

It's for rcs. My pH is a 7. It's not a huge scratch so do you think it'll be fine? Just don't want to spend a load of money on rocks lol

 

It's for rcs. My pH is a 7. It's not a huge scratch so do you think it'll be fine? Just don't want to spend a load of money on rocks lol

Do u have an api test kit if u do take the NITRATE BOTTLE #1 and put a drop on the rock if it has any reaction don’t use it it’s similar to the vinegar test but it’s a stronger acid