Personally I would say your tank is pretty much stocked. Uaru are pretty big fish fully grown and will fill your tank nicely.
I'm also a firm believer that less is often more. A little self control in a fish shop can sometimes make a display look better. Must admit I have trouble practicing what I preach in this regard.
My tetra and ram tank is 210 gallons, it has 11 rams and about 180 black neons and around 30 bentosi tetra. I've recently added 9 peruvian angelfish to the tank.
Regarding the light yes I think a 3feet tube will do the trick.
I sometimes put silver foil under part of the light to create shadows.
Growing algae is easy. Do smaller water changes for a while, increase your lighting hours and if possible let natural sunlight hit your tank.