But I still have to move the tanks to the area I mentioned before, and they would need a shelf for that. As it is now, I would have to cover up the front and sides of the aquariums if I want to be sure there's no chance of sunlight hitting them. Due to the arrangement of my small room, the only thing I can think of is to shift furniture away from that wall and put the shelf against it. There's a really huge window on that wall (takes up a lot of the wall); a shelf with a back or a cover will likely protect the tanks from the heat of the sun, as well as the rays. I can't use the other side of my room because the wall there is entirely made of large sliding closet doors.
I'd like to add that I don't want to hide my tanks away (such as in the closet), I want to keep them by my desk. So for this plan, my desk would move farther from the wall and the shelf would occupy that area, so that I can keep an eye on the tanks while I work.
The setup of the tanks currently is one on the nightstand, one on top a low bookshelf with a divider in the middle under it, and one on the desk. It's all a very cramped space. But the way they are, I realize that even with half the window boarded up, there's still some light in that direction when the sun is at midday to evening. I think it might be the reason I'm having so much algae problems in my 5 gallon, because I didn't have them before when it was on the dresser on the other side of the room (moved it because I wanted to be able to see it).
I'd board up the other side of the window except that my elderly cat only keeps herself to my room and she loves looking out the window.
Update: Going to go by Home Depot today to look at the shelves they have in stock. I'll take the advice from above and look not only for metal, but sturdy wood as well.
Update #2: Been thinking it over (haven't gone to HD yet), and I'm thinking it might be better to get two low shelves rather than one really tall one. I couldn't mount a tall shelf properly being that the window is mostly behind it, but also it would have a lower center of gravity, and allow the cat to walk on top to her cat tree (I love dis kitty). So I'll look for a sturdy wooden or metal shelf that's around 46" tall, and put the aquariums on the top shelf, and use a divider on each shelf below.