Can You Tell By The Looks If A Rock Is Okay To Put In A Tank?

Here's a rock I found in a nearby forest/park that I wanted to put in my tank.

I boiled this rock two times and that's all I've done with it. I picked this rock out for the other angles of it that aren't displayed in the photo. I took this photo to show you guys what looks to be the 'bad' part of this rock.

It seems to have some red on it, this part of the rock is the only bad part, the rest of it looks fine. To my understanding redness indicates iron. I do have numerous plants and the only thing giving them nutrients is my substrate. So would this bit of iron actually be good for my plants?

I'm new to the aquarium life and it will become a hobby to me as I enjoy the nature life aspect of it so I will try to spoil my fish lol.

 

I'd perform an acid test, if the rock fizzes I wouldn't use it as it would raise the the pH and hardness of the water.

 

Hi, looks like a good piece of rock, as you say red colouring is usually caused by oxygenising of iron in the rock (basically rust) so if you have red coloured plants in your tank they will benefit from the iron leeching into the water column. What part of the world are you from & what sorts of rock are common in your area? I would caution against putting sandstone or limestone into an aquarium but that piece looks more like granite, what does it weigh? If heavy make sure you cushion it well so it doesn't put too much weight stress on the tank base.

 

Short answer is yes you can look at a rock and know whether it’s safe or not BUT it helps to know the geology of the area the rock was collected from.

Looks like granite to me as well. As noted above try the vinegar test to confirm.

 

I read nitrate solution #2 is a good liquid drop test chemical for rocks. Better than vinegar.

 

I'd say yeah. if your rocks have any metallic material in them or crumble it probably not good to use. Be careful with that rock, it looks like it had some sharp edges.

 

I used boiling water on my rocks as well, but also scrubbed with a wire brush to dislodge anything like caked mud or similar elements. Acid test, and a hot scrub, and you should be good.