Is it a bad idea to add these rocks?

[Bubblebass]

I am looking for some contrast in the aquascape of my 120g. I have plenty of rock and the tank is almost 3 years old. I want to add these rocks that were at my LFS for some shelves and contrast. It was sold to me for "planted tanks", but I want to put coral on it.
From research, sounds like I should put them in a bucket and change the water for 6 weeks. Do I need to do all that when I'm adding 6 pounds of rock to the 150 in there already? I washed them and used a brushed until the water came out clean.

Thoughts?

 

[saltyfilmfolks]

I belive , the actual concern is that the rock is inert. Limestone is not, it’s slightly reactive and also easily dissolved.
I’d check out the type of stone it is.
The one on the right I’m prettty sure is ok. The left I don’t know.