GFO granules or pellets???

[Dave VG]

They say pellets have the edge and i quote from twopart.

Pelletized GFO features advantages over the granular form. The pellets are harder and lose less material into the water. They also contain more iron and will remove more phosphate by volume.


what do you all use?

[jdieck]

I had the oportunity to test compare pellet vs granules.
The main findings were:

a) I was not able to test if the pellet loose less material or not than the granules but it is noticeable that pellets are easier to rinse and have less fines than granules

b) Pellets provided a better flow distribution troughout the media bed than granules, this seems to have reduced (but not eliminated) the media tendency for clumping together due to calcium carbonate carbonate precipitation thus extending the useful life of the media allowing for enough time for complete depletion.

[pjf]

Has anyone had a chance to perform the same comparative test with Warner Marine's PHOSaR HC? This granular GFO is denser than its competitors and should be more durable.

[pjf]

Here's another consideration in favor of granular GFO (http://www.pets-warehouse.com/carbon.htm):

'As a rule, the molded “pellet” type GACs were less effective in removing color than the other brands. Three of the four lowest adsorbing carbons were pellet shaped. The pellets had smooth, hard surfaces. The most effective carbons tended to be irregular in shape and offer a large surface area to volume. The surfaces of the more effective carbons were rough rather than smooth like the pellet carbons.'

[jdieck]

Originally posted by pjf
Here's another consideration in favor of granular GFO (http://www.pets-warehouse.com/carbon.htm):

'As a rule, the molded “pellet” type GACs were less effective in removing color than the other brands. Three of the four lowest adsorbing carbons were pellet shaped. The pellets had smooth, hard surfaces. The most effective carbons tended to be irregular in shape and offer a large surface area to volume. The surfaces of the more effective carbons were rough rather than smooth like the pellet carbons.'

We need to be careful here as the comparison may not be extensded to other medias, GAC has a totally different crystalography than GFO also GAC does not loose performance because of precipitation on the surfaces.