To answer the op's question, yes, denitrators can work very well.
Just like having a system to remove phosphates, i.e., GFO, most aquarists find that they need a system for removing nitrates, I.e., denitrators.
They might be your best bang for the buck in the long term and easiest to maintain, however, they have their caveats, such as with a sulphur based if you don't keep an eye it it it can produce gas that kills everything in your tank(this might be rare, but worth noting).
Large weekly water changes are easy....if your tank is less than 100 gallons or so.
Carbon dosing, I.e. bio pellets, Vodka dosing, VSV, vit C, etc.
Seachem Matrix rock can assist.
Activated carbon can also assist.
And there are more....
Definately research before you do any and multiple, as all have caveats.
I dose vodka, change high quality carbon weekly, skim, large water changes, and use Seachem matrix and my trates in a heavily stocked tank stay around 0.5 over the long term.
I use GFO for phates (1 cup of HC GFO) that I change weekly (even though some of the other things that I do to degrease nitrates, does help phates, it's not enough for SPS.
And more...
