You have a few options with nanos.
1. You can go skimmerless, but you must do weekly water changes to export the nutrients.
2. Custom skimmer to fit in. (nice fit - but expensive)
eg:
http://www.nanotuners.com/product_in...roducts_id=358
3. Cut the canopy to accept a small skimmer like the remora aqua c.
4. Drill holes and run a external sump.
Each has its upside and downside. Nanos are interesting that way. Check out
www.nano-reef.com
www.nanotank.com
For other ideas.