Removed tank hood, new lights, now what?

[Scuba Diver Gal]

Our heater is a 100 watt marine land submersible heater. When we were starting we went to Big Al's and some guy gave us everything we would need for the Biocube. Since then I am realizing that maybe some of it wasn't the best quality. it's only been a few months but there sure is a steep learning curve to this hobby. And some bad decisions/purchases along the way...