Hmmm interesting I was under the orginial impression that nano tanks took a lot more effort than the larger counterparts. Been doing a little bit of reading and it seems they aren't as bad as they used to be. Oh sooo tempting.
In a way I think they are, you have less space for pumps/heaters etc. Mine doesnt have a protein skimmer so water changes should probably be more frequent. As the volume of water is small, things can go wrong much quicker than a larger tank so keeping on top of water quality checks, topping up evapourated water etc, dealing with temperate fluctuations etc can be more important.
I got mine after I got the larger tank so if something did go wrong I could transfer the live stock to the big tank.
I did have a nitrite/nitrate/ammonia spike in the nano once (when we returned from holiday and I think the tank had been overfed), I didnt need to move the livestock as I just did a few large water changes.
However saying all of that I swapped the halogens that came with the fluval edge for LED (hoped to keep the temp stable), I probably only top up with RO water every 3 days or so and the glass doesnt seem to need cleaning that often. I no longer bother testing for nitrites etc regularly (but I keep an eye on the fish behaviour). I need to sort out some additional lighting to keep corals though.
If you do go for a nano marine I would advise:
1. keeping spare salt water (at the correct salinity) and RO water to hand for emergency/evap top up.
2. Do tests regularly including oxygen, I added an additional powerhead as the waterfall filter didnt really suffice for agitating the surface.
3. Dont put too much livestock in - the more you stock the more frequent your water changes and the quicker things can go wrong
4. keep an eye on the temps as a small volume of water can change temperature much faster
5. Dont overfeed
6. Stock hardy fish (clowns are fairly robust) - this way if something does get out of wack you might not end up with dead fish
I've got 2 clowns, 1 hermit and a snail in mine. I might put in a cleaner shrimp in the future and more corals but If I add any more fish it will be 1 rock goby.
I have thought about getting another or moving the fish to the big tank and getting a mantis shrimp.
Some good info can be found on ultimatereef.net for fluval edges.