Are R/O units a must???

[fishyshawn]

Is an R/O unit a must for a reef aquarium what if i didnt have one would the inverts have a hard time and die.

[jerryc]

Most of the time YES.
But a few luckier ones live where the water is good enough for reef use
get a TDS meter and check your water it will answer your question.

[davejnz]

Its not a must if you don't mind buying distilled/purified water from the grocery store for top-off.When buying water from the grocery,make sure you read the fine print on the label.It tells you how the water was filtered.I used "Purified Water"from Publix before,on the label the filtering process used is,carbon,RO,and DI.Stay away from the "Spring water" or "Drinking water" as these are only sediment and carbon filtered.