some of new owner still dont buy heatpad or UTH,but i have a solution for this(use as an alternative,not advice for use long term).make sure ur tank or tube have high legs or you can put your tank above some book or wood to make a big space below the tank.boil water,let it cool to 90F to 100F.then put it in a bowl n place it under the tank right below the hiding place,this will heat for 1 or 2 hours depend on your room temp.change the water if it already cool.hope it help u.