Activated Carbon for Spider Farmer inline fan

[MiguelEnfermo]

Greetings Growers, Since Spider Farmer doesn't sell the activated carbon pellets for their own inline fan system, does anybody have a favorite go-to for replacement carbon pellets? I asked the SF sales guy and they said they don't sell refills and get the 4.5 mm pellets. Yay.
Any suggestions on what you folks use that works with this duct?

 

[Bowhunterwoody]

I've never replaced the activated carbon in a filter. I'm interested in how it works out. $40 for a new filter every 2-3 years seems easy enough but if it saves enough then

 

[Orggrwr]

I have 2 of the AC Infinity refillable filters and they work great. AC also sells bags of loose carbon that should work fine in Spider Farmer filters.

 

[dmpmfd]

Greetings Growers, Since Spider Farmer doesn't sell the activated carbon pellets for their own inline fan system, does anybody have a favorite go-to for replacement carbon pellets? I asked the SF sales guy and they said they don't sell refills and get the 4.5 mm pellets. Yay.
Any suggestions on what you folks use that works with this duct?

Not knowing the brand, are they built to be refillable or disposable?