granules or pellets

[ChillingBoy]

can i used the Granular Ferric Oxide PELLETS in the reactor?

[JetCat USA]

it's less efficient but yes you can use it.

[Snarkys]

the pellets are almost the same size at the granules , just slightly bigger. The main difference is the pellets are harder so they release fewer fines into the water . Pellets also contains more more material for the same amount of volume . The materials are extremely similar , the pellets just have slight advantages.

I personally don't see any disadvantage to using them in a reactor.