to each his own. My nitrates stay between 5 an 10 on all my tanks. I have no issues there. Your correct your water has no BB.. but it does produce bacteria.. no matter what you do.. chemicals from your water lines, water system will be in your new water. You seem to already be an expert so you got it down. No need for me to try an help you out. If you think your reds color is brilliant that is all what matters. They are your fish. none of mine have ever looked like that though. You def. did them right by saving them from the 30g. You got them in a 400g now right? That's much better. Good job man