New MarcoRock brown

[stoney7713]

I got some MarcoRock from BRS awhile back and had a few pieces that has a lot of brown on them. It doesn't wash off or scrub off. Anyone else experience this? You think it is safe to use?

 

[reefsaver]

My first assumption would be it's just Iron/iron oxide that is just apart of the sedimentary composition of limestone and/or the calcium carbonate that makes up the stone. Literally harmless, maybe a tiny amount will precipitate over time but I would say a super negligible amount. Hell trace amounts might actually be beneficial. If you absolutely hate the brown, maybe give it a test in some Vinigar, although I'm like 60% sure the Rock will dissolve as well as the iron oxide.

 

[stoney7713]

My first assumption would be it's just Iron/iron oxide that is just apart of the sedimentary composition of limestone and/or the calcium carbonate that makes up the stone. Literally harmless, maybe a tiny amount will precipitate over time but I would say a super negligible amount. Hell trace amounts might actually be beneficial. If you absolutely hate the brown, maybe give it a test in some Vinigar, although I'm like 60% sure the Rock will dissolve as well as the iron oxide.

The color doesn't bother me, it won't stay white anyways.

My main concern is what is it and would it leach out and harm the tank.

I thought maybe someone else has seen it before.

 

[reefsaver]

Yeah my best guess would be iron/iron oxide. Which is typically brown to reddish, before I posted I quickly looked up whether or not Marco Rock actually can contain iron/iron oxide and it can. I read this: limestone, sedimentary rock composed mainly of calcium carbonate (CaCO3), usually in the form of calcite or aragonite. It may contain considerable amounts of magnesium carbonate (dolomite) as well; minor constituents also commonly present include clay, iron carbonate, feldspar, pyrite, and quartz.