Do I really need an RO unit ?

No--and I would wonder about drinking it.

Nitrites and Nitrates are all stages of nitrogen decomposition. Ideally, aquariums test nitrites at 0, and nitrates under 20 ppt. Otherwise, the numbers look pretty good. Rather than going with RO, you should be able to run your water through an inline filter marketed to remove nitrites. A bit more than charcoal, but it will pull out many of the nasties if used properly.


You may need to supplement your water with calcium, depending on what else you want in there. You do know that there aren't that many low light corals that do well in the home aquarium? Most low light critters are from deeper waters, and tend to prefer cooler waters in addition to being hard to come by. You might want to look into sponges instead--they have different needs, but don't require lots of light and come in some neat shapes and colors.