well if we exclude the tank and stand
1, MH lighting
2, good skimmer (Island aquatics)
3, Ca reactor (Island aquatics)if you keep more than a couple SPS, I have been missing mine sence I moved and boy do I miss it.
anything else is gravy, you can get buy with out RO by buying bottled water as I did at first (only the initial fill is a pain) and if you have a nano or sub 50 gal tank a RO will take a long time to pay its self off if only used for the tank.
Steve
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*everything said above is just my opinion, and may or may not reflect the views of this BBS, its Operators, and its Members. If cornered on any “opinion” I post I will totally deny having ever said this in a Court of Law…Unless I am the right one*
Some strive to be perfect.... I just strive.