First off there are thousands of DIY skimmer plans on line. Just search DIY nano skimmer, or something similar.
I was originally drawn to doing a DIY skimmer for my JBJ 28 from THIS article on Reefbreeders. I had the wood air stone and tried this skimmer with the air pump I had. Eventually, going back to this article and researching air pumps, I realized this guy was using an $80+ air pump. At that point I went out and purchased a Tunze 9002 and haven’t looked back.