What size UTH works best for a 20L? Seems like a lot of companies have a UTH for 10-20 gallons, but I'm thinking that will be too small for the 20L as the 20L has the same footprint as a 29.
I mostly use heat tape that I can put in any configuration, but I do use the 10-20 gallon UTH's for my 20 long and the mini (1-5) for my 10 gallons. I sell setups that way because with tile flooring, those sizes for the most part keep the temps correct without thermostats.