I've looked at it on the shelf, just out of curiosity. Its not worth the price. If it does work, it will only bring nitrates down by 5-20ppm for a short period of time. It is an ion exchange resin, removing ammonia & nitrate ions and replacing with sodium ions.
Best way to control nitrates is through water changes.
I do run some ammo chips (zeolite) in the canister of my mbuna tank to remove as much ammonia as I can before it converts to nitrate, but Its an overstocked tank and It isn't a substitute for water changes.