the walmart stuff is cheap, but it is not Black Diamond.
A search of Reef Central shows articles with tests of activated carbon (AC) effectiveness. The tests place SeaChem Labs Matrix in first place for effectiveness with Marineland Black Diamond in second place. But are they worth the price?
Using EBay and Froogle, I just examined the prices of 30 ACs (6/3/2006). Cheaper brands were Marineland Diamond Blend (which is only ½ black carbon), generic Premium Activated Carbon Charcoal+Extras, Aquarium Pharmaceuticals Activated Carbon and Ammo-carb (1/2 blend), Pro Line Activated Carbon, generic “7 and 9 pounds carbon†on eBay, and Black Magic Super Activated. These ACs are all less than $.22 per ounce without shipping, except for the Premium Activated. This carbon comes in 400 ounces (25-lbs.) and ships in the US for $19, or $.12 per ounce!
The average size in the study was 91 ounces (5.5 lbs.) for an average of $26.55, or $.43 per ounce (without shipping).
Black Diamond is available online at That Fish Place for $14.99 in the 68-0unce size, or about 0.22 per ounce.
Who is using what ACs, how much per gallon and why?