20L Tank with 5x8 uth on left side. The 5 is on the long end. I want to get rid of over head light and get another uth. Should I get one to fit the rest of the tank or just the other side? Plus it is it ok to have the water bowl over a uth (outside tank) or not. Seems to be some disagreement there. Any input would be appreciated. Looking at a Herpstat II to manage heat.