Yup. Rich is THE man to talk to about that...he's awesome and incredibly helpful.

I've used both ZooMed (the main thing I have now since I get discounts at Petsmart) and Ultratherm and they both work fine. The Ultratherm is thinner, uses less electricity, supposedly never gets over the high 90's in temp even if full on, and is cheaper than the ZooMeds tho.

But for ultimate low price, the flexwatt wins. It's only a few dollars a foot and is said to last years and years...but you NEED a thermostat with it since it gets even hotter than the pads. But, since you're already getting a good stat, you should be just fine.

Since a 20L tank is 2.5 feet long, and a 10 gallon is 22" long, you'd probably need one 10" piece of 11" flex, and two 7" pieces of 4" flex for the 10gal. But that's just my estimate. Ask Rich to be sure.