Looking for information on Nitrate control


What the difference between and what anyone opinion on which is better.

BioPellet Reactor (not sure what brand)

Korallin BioDenitrator S-1502

Cost is pretty straight forward on the Koralin, but the Bio pellet reactors are all over the place.
I have a 120 gallon tank with sump not sure what size Bio Pellet reactor would work best.

Also has anyone used Continuum Aquatics Bacter Gen-MD as another option?