I have tried Orca, back then was polyplabs like 10yrs ago, then Sharks, then now Orca.
While they are good at bringing down nitrates im 2weeks. It needs a strong air pump, get those meant for pond. Works better. Otherwise normal air pump cant support the requirement and u will likely end up wasting ur nitracubes.
Please note orca can cause some cyanobacteria. This is especially true when ur no3 reach a certain level with ur po4.
Since u are investing so much and planning to go sps, please get hanna checker for po4.
Also, i noticed that my no3 dropped from 10+ to 2ppm after using zeomix in a reactor/fluidized resin filter. Can try that.