^True but its a lot easier to do a WC on a nano than a bigger tank
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What nano did you get/are you looking at?
The good thing about nanos is that you can get by with less. For example, with a nano you stand a better chance of success should you choose not to use a sump and a protein skimmer. Because the water volume is small, making water changes easier and cheaper, more frequent and/or larger water changes can be done to combat nutrients. Likewise, the same water changes have a greater chance of replenishing elements without the need for, or at least reducing the amount of dosing for Ca, Mg and alkalinity. I am a big believer is using a good skimmer unless the tank is really small.
Bad thing about nanos is that you are limited to what you can keep (mainly fish). Also, if you end up going with a manufactured all-in-one (Biocube, etc), you are pretty much stuck with the lighting, etc. that is comes in the box. Yes, you can replace/modify, but why pay for things twice?