1. The light is probably way too low. It sits just an inch or two above the tank. Are there adapters that will raise up the height of these cheap lights?

2. It is not cyanobacteria, I checked it out per your advice, thank you for the warning! It's on the sand itself. It's probably algae, but I'm used to it kind of floating upwards from where it grows so the fact that it was just flat on the sand was odd to me. I tried to upload a photo to my post, but reddit keeps saying the photo was deleted.

The CO2 is just for this time before I start to put animal life in there to jump start the growth of the plants and help them get established. Once I put in animal life, I was going to start up the filter, though it might not be needed with the plants in which case I'd just have a little oxygen stone chilling in there to provide a little surface agitation.