I vote water changes, but that's because I know nothing about NovAqua+ and don't know anyone who uses it. I'm always a little leary of using anything chemical when just a little leg work or elbow grease can get the job done just as well (have had some bad experiences with pH balancers before I knew better as well as algae destroyer stuff...before I knew better).
For me the way I look at it is adding any unnecissary chemical is risky. If you can fix a problem with a little more work and not use it then why wouldn't you? The only "chemical" I use on a regular basis to water conditioner. But that's just my two cents.
I agree with Ken. The water changes are necessary, and will remove some ammonia but not all of it. The detoxifier will make the ammonia not as dangerous for the fish until the next water change.
Nothing replaces a good water change. Water Conditioners that detox ammonia (like prime and aqumel+) are like a band-aid, they cover the wound and make it feel better, but don't fix the problem. You'll still need Water Changes for that.
If you're using RO water, you will need to use buffering agents like Kent's R/O Right or Seachem Equilibrium--don't forget about that.
And you definitely need to do 100% water changes to remove ammonia--since the ammonia is coming from your fish and not from the water (given that it's RO water) you should definitely should consider some live plants and increasing the frequency of your water changes until the tanks are able to complete the nitrogen cycle.