If you don't mind outfitting your 10 gal with pressurized CO2 or adding a canister filter to your nano, then this won't interest you. I like doing things the cheap way, not because I can't afford that green canister filter, but because I get a kick out of some good value.
So here is a cheap way to get
installed in your tank without spending big bucks. Plus, all the stuff is sort of hidden, and in the tank. Hidden behind a sponge, which isn't that visible at all. In the tank, meaning there are no leaking connection problems, heat losses, head to overcome for pumps, etc.
Here is what you need... A powerhead (~$20) some sponge pad ($5) some plastic pipe for the outlet/spraybar ($1) and miscellaneous stuff like an empty plastic bottle (free, find in trash). A heater of course, ~$10.
A picture is worth 999 words, so here is my wonderful drawing:
I have something like this working for almost 3 years with different designs. First I used the impeller of the powerhead to disperse the CO2. Later an inline internal diffuser. I used a loop over the sponge to return the water to the tank. Many things. In the end often the simplest design is the best one.
Couple of design details... top is from above, below is looking into the tank, with the sponge "cut" thanks to MS Paint
The red circle is the heater. Good place to hide it!
The pink line is the CO2 supply. It is twist-tied (yellow) to the side of the plastic bottle. Bubbles raise up and are sucked into the bottle. They go to the top of the bottle, but there's a whirlwind in there that dissolves them in no time!
The (green) sponge is cut and the powerhead outlet stuck through it and connected to the spraybar. Water returns through the sponge.
Obviously this is better for a low maintenance tank. I clean the sponges once a year or so... the rest is taken care of by bacteria. The tank is severely understocked.
This is a 43 gal tank, and I am using a AquaClear 50 pump, which is about right for that purpose.
Simplicity is the key