I might be setting up a reef tank soon. What’s a good size that doesn’t need a sump but large enough to have a few small fish? Is it cheaper to mix water or buy water? My lfs sells saltwater for 99cents (us) per gallon. I’m thinking of buying this ro/dI system . I will probably do fowlr first then add some corals when the parameters are stable. Are there any cheaper lights that can grow soft corals and lps, or are they all $100+?