my leds are super bright, looks like you shot those with lights out in the room, can see the tank more clearly. You could always make a diy co2 kit. Just need a couple of gatorade bottles (one for yeast and one for bubble count/more of a dump tank) There are plenty of diy plans for this online, Im sure there are some in the diy section on this forum. I would suggest using co2 proof tubing and definitely getting a quality check valve as normal airline check valves gunk up in a hurry from the co2. You are right, you probably don't need it, but couldn't hurt either. Only costs maybe 15 bucks max (if you have some form of diffuser) and a diy co2 shouldn't produce enough co2 to ever be harmful to the fish. i run mine to a mini water circulator that faces down in the tank and secured a hose with an airline tip pointing straight up under the propeller, bubble rises gets smashed by it. Just an idea if you ever did want to add co2 and didn't want to cough up all that coin.
Once again, good looking tank, best of luck!