Ceramic Heat Emitters?? What size

[2006gt]

im getting a 20 gallon long setup for a Future bp i have a 10 gallon with a 60 watt CHE and half covered with a towel and it stays 80-81 ambient and a hot spot of 91-92 and she does fine i was just wondering what size CHE i can use to keep the 20 long around 80-81 ambient. thanks if you use one let me know what size and what size tank. i find it keeps the humidity better with forest floor/reptibark combo and i mist every other day thanks alot