Marineland Black Diamond Premium Activated Carbon

Marineland Black Diamond Premium Activated Carbon is loose carbon for the chemical stage of an aquarium filter. It removes odors, discoloration and dissolved impurities, leaving water clearer. It’s made from heat-activated, bituminous coal-based carbon and sized to keep working, Marineland says, longer than other carbons. This page covers the 22 ounce and the larger 40 ounce containers.

What carbon does

Activated carbon is full of tiny pores. Dissolved organic compounds, the ones that tint water yellow and cause smells, stick to the surfaces inside those pores. Once the pores fill up, the carbon stops working and needs replacing.

Using it

• Rinse it in a fine mesh bag under running water until the dust clears.
• Place the bag where water flows through it, after the mechanical stage.
• Replace it every few weeks, or when the water starts to yellow again.

Marineland says it suits all aquarium filters, from hang-ons like the Penguin 200 to canisters like the Magniflow 180.

When to take it out

Carbon also removes many medications. Pull it out before you treat the tank, and put fresh carbon back once treatment is done to clear what’s left. In planted tanks, some keepers skip carbon, since it can take up some liquid fertilizer.

Which size

The 22 ounce tub is plenty for one or two small tanks. The 40 ounce container makes sense for large tanks or several setups that get carbon every month.

Who should look elsewhere

If you’d rather not keep replacing media, a regenerable resin like Seachem Purigen targets organics and can be recharged.