Rock question?

[Sparky]

I asked this question on another thread last month and did not get any answers.

I have some rock that I found. It is flagstone. I have pressure washed it and it is setting in the garage. I wanted to use it to build a base wall in my tank, but I am not sure if it is OK to use it or not. Can anyone help here? I would appreciate any help on this.

Mike

[ellisz]

Not sure if this is a definative answer or not but put it in water and see if it leaches PH or not. I know the agrocrete stuff I made caused lethal levels of PH for months. Never really saw it lower ... gave up.

HTH

[reefrunner69]

What is the composition of flagstone? Aside from the possibility of contaminants that may have soaked into the rock, that would be a deciding factor.

[Sparky]

Thanks for the quick reply. I think it's main compostion is limestone, not sure though. I will see what I can find out. Again thanks for the replys.

Mike

[Sparky]

OK this is what I found on the internet concerning flagstone. I also got a picture of it that I will post also.

"Tan to Brown in color with moss. Rough sandstone that varies
in thickness. Commonly called "Waterfall" rock. Easy moss
growing flagstone.
Colors ranging from light to medium tan with swirls of
pink and rusty hues on most of the stone. Moderately
hard smooth sandstone."

[Sparky]

try it again

[RogerMcAllen]

I don't think limestone is a very good choice for aquariums, as I am fairly sure it will leech into your water and make it very hard. Try putting some vinegar on it and see if it fizzes. Fizz means that it is a poor choice for your aquarium.

[dralarms]

Fizz means that it is a poor choice for your aquarium.

But the sand we are all trying to fins fizzes.

[reefrunner69]

Yes please remember this is a SW tank, LR is mostly limestone, however, sandstone and limestone are not the same (are they?). I would be concerned about the mineral content of sandstone. Personally, I suspect this rock will have a high metal content in it, and possibly some food for nusciance algae.

[dralarms]

I suspect this rock will have a high metal content in it, and possibly some food for nusciance algae.

I agree. I am using "flag stone" (I call it slate) in one of my tanks as a temp "cave" and I have a green hair agae bloom that is wild. However my snails are tearing it up.

[Sparky]

I am do to change out some water this Sunday. About 30 Gallons. I was thinking about putting that water into a garbage can and running a PH for a week or two. I was thinking of putting the rock into the can and see what happens. Since I am not sure what the rock is made of I really don't want to put into the tank. I do know for sure it is not slate or granite. It has to be either limestone or sandstone. I am leaning toward the limestone because it is plentiful in this area. This rock has been setting in this area for at least 50 years.

Anyway, what should I be looking for if I was to put into the can with my change out water from the tank?

Thanks for all the replies.

Mike