Yes, it is very possible. It is possible to build one in a 1 gallon tank. However, it will be difficult with keeping up with evaporation and all that other stuff. BUt yes, 10 gallon's are a very common refugium, nano, etc...
Possible but as I am learning I am glad I went with a 55. They cost about the same except a little extra cost for a 55 gallon tank versus the smaller tank but much easier with the bigger tank. If you forget to top off(which I am trying to remember) you will spike salinity redeiculously with a 10 when in a 55 it will not be so bad.
Rich
not exactly for experts (it can be done easily).... what i do (kind of ugly) is put a piece of tape on the aquarium. I then use a sharpy and draw a line over the water where the salinity is perfect. every day i pour distilled water if it goes down. works beautiuflly... and it's cheaper that way too with lights and that kind of stuff... i'm think of going for a five or one gallon nano soon... it hsoudl be fun
10 gallons are tough, period. If this is your first saltwater tank it will be a very expensive one. If you want a small tank a 29 might be OK. Do your research. Good luck!
Ken
A 10 gal can be very expensive if you are not experienced. The cost of setup is not bad but once you factor in mortality rates they are not cheap. I'm not saying a 10 gal cannot be your first tank, it's just that if you don't do your home work it's going to cost you $$$.
Ken