I'm starting a tank dedicated to propagating bubbletips. It is a very basic setup. 29 gallon, air stone skimmer, powerhead, heater, ebay LED light and a hang on aquaclear filter. I put the filter foam and ceramic bio-rings in my established reef tank about 4 months ago to get them seeded with bacteria. Should I use any "water change" water from the existing setup or use all new saltwater? Also, I know nems are best only introduced to established tanks due their sensitivity to swings. But, with this being a dedicated system for only nems could they be introduced earlier. It will be a bare bottom tank with maybe one or two small fish down the road. Will the bio-rings be enough biological filtration for this small bioload? Should I get some kind bio block for additional biological filtration? Any input is appreciated. Thanks everyone.