Contamination in carbon from bituminous coal

[BranchingHammer]

Hello everyone,
So I have a container of Marineland Black Diamond premium carbon, which is made from baked bituminous coal. Today, out of curiosity, I ran a magnet over a small tray of the stuff. To my surprise, almost half of the grains proved to be magnetic! Interestingly enough, the magnetic grains were larger and darker, while the smaller, grey grains were non magnetic. I am assuming that this is due to iron or other metallic contamination within the coal. I know that iron is pretty safe for reef tanks as it is metabolized by chaeto and corals etc., but what if there is other metal contamination in the carbon? Is carbon able to release these metals as ions when immersed in saltwater, or is it relatively inert? I’m thinking of switching to ROX carbon because of these results... What do you think @Randy Holmes-Farley?
Here is a picture of the two types of grains in the carbon: magnetic on the top and non magnetic on the bottom.

 

[Cory]

This is interesting! Sorry i dont have an answer but you could soak on ro water and do an icp test of that.

 

[BranchingHammer]

This is interesting! Sorry i dont have an answer but you could soak on ro water and do an icp test of that.

Good idea, it would be an interesting experiment to do. I just figured since this carbon is sold and used pretty widely, someone would have an experience to share. I also read that this type of carbon isn’t used in drinking water systems because it can release harmful chemicals. So why do I have it sitting in one of my drawers for my reef tank? What do you think @Randy Holmes-Farley?

 

[BranchingHammer]

For example, BRS sells it, and many people use it without issue. Just really weird to see my carbon levitate like space rocks when exposed to a magnet...

 

[Randy Holmes-Farley]

I'm not a fan of Black Diamond. I used it for years, but switched away to ROX 0.8 out of concern for HLLE types of issues in yellow tangs. I didn't have the issue after the switch (where I did before), although I cannot prove it was the cause since it was not the only thing I changed (I also stopped using ozone).

 

[BranchingHammer]

I'm not a fan of Black Diamond. I used it for years, but switched away to ROX 0.8 out of concern for HLLE types of issues in yellow tangs. I didn't have the issue after the switch (where I did before), although I cannot prove it was the cause since it was not the only thing I changed (I also stopped using ozone).

Do you think the carbon is actually able to leech metal contamination into the water?

 

[Big E]

I've used Black diamond for years and never had any issues with lateral line on tangs...........Yellow, Purple and desjardini.

There are many better brands so I probably wouldn't recommend it. Back on RC there were some great write ups by Boomer about carbon if you can find them.(search the archives) He went into great detail about types and brands.

Black Diamond is fine to use occasionally to clear up water or remove something short term but if you're going to run carbon 24/7 I'd probably go with other brands. It's important what type of carbon you're buying more so than brand.