When you do your nitrAte test, be sure you are reading the full directions. It's different than "water, dropper wait read" You have to shake the bottle #2 for 30 seconds, violently to break up the crystals.
You have to combine water +bottle#1 then add the drops from shaken bottle #2, after you do this, you have to shake the final combination for 60 seconds, wait 5 minutes then read it against the card.
I would put some of that RO waste water in there, but make sure you do a VERY large water change before you add your fish, since the waste water is highly concentrated wastes/yuckiness.