New upgrade

So I just upgraded from a 36 bow to a 55 truvu and I still have some gha from previous tank. Previous tank had no sump but a 305 fluval canister tee'd to a phosban 150 with gfo. New setup has a eshopps rs-75 with a swc 120. My question is whether to run gfo off of my mj400 or switch to npx pellets off of mj1200? The plan is med-hev bio load. I have 2 ecotech radions, mag 7 return, 1 mp10, 1 hydor 750 that will be switched to a mp10 and no refugium. The gfo or bio pellets are already purchased but almost out of gfo. Pellets are unopened. Nitrates are a little high for me 20ppm'ish. Phosphate are at 0 but could be false reading due to to gha. Mag Is around 1300-1400 on salifert. All others on API. I also just tore tore down a 5.5 gallon tank, could I somehow use this as a refugium?

 

Sorry forgot to add went from odyysea 4 bulb w/geisemann to reefbuiders 120w to 2 radions.

 

I would not advise the use of pellets; While a few have had success with them, from what I've seen here the majority have not, and in some cases, they caused harm to livestock. IMO, more research needs to be done concerning proper application. OTOH, GFO would definitely reduce phosphates, and GAC would help lower the production of nitrates by removing organics that the skimmer misses.