NANFA-- Carbon vs charcoal

Hoover, Jan J ERDC-EL-MS (
Sun, 3 Jun 2001 20:04:46 -0500

The filter carbon I have used for several years (Brand A) is shiny, large
(10-13 mm max dimension), heavy (approx 17 g/20 ml vol), and clean
(requiring only 3-5 quick rinsings).

The filter carbon I was recently supplied (Brand B) is dull, small (5-9 mm
max dimension), light (approx 10 g /20 ml vol), and dusty (requiring
innumerable rinsings; 20 or so will get it clean, unless you increase water
pressure and then water washes off black again; I believe this brand is so
soft that rinsing it breaks up the carbon and generates new dust that did
not result from packing, moving settling, etc.).

When I was a kid working in a pet shop, we referred to Brand A-type carbon
as "carbon" and Brand B-type "carbon" as charcoal. At that time (1970s),
at least one pet supply company sold both a carbon and a charcoal version of
their product. The former was a little more expensive than the latter and I
believed then that it was a better filter medium. I believe that now, too,
as Brand A is sufficiciently dense to weight down corner box filters,
sufficiently large not to pass through pores of our homemade gravity-fed
filters, and it does an excellent job of keeping water clear in our large,
sometimes overcrowded tanks.

My questions:

Are the two types of carbon functionally different from each other (does one
filter differently or better than the other)?

Is there some advantage to the softer, lighter, smaller carbons that offsets
the inconvenience of using them (e.g., extended rinsing time, weighting down
corner filters, etc.).

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