I also agree with Al that the containers probably aren't the cause of the algae.
I think we're also overlooking the fact that the clean-up crew consists of 3 astreas! There is no way they can keep up with the detritus and larger wastes such as uneaten food. I would try to get dozens more of each astreas, turbos, nerites, nassarius, etc, etc, and a couple Mexican turbos as well. A variety of snails, and a lot of them, is very important. I only have a few hermit crabs. I have my reasons, but they can be very helpful in dealing with algae, detritus, and wastes.
From the pictures you posted, the algae problem doesn't seem that bad and a much, much bigger cuc will make a big difference. If you can get a sea hare, it will be a huge help. It looks to me that you just have the standard turf algae that newer setups usually get. I don't put in corals or fish in my tank until it has gone through the various algae phases that new setups go through and is fully cycled. I'm still kind of old-fashioned and wait a good amount of time before adding fish or corals. I always wait at least 3 months, usually 6 or more. This is just what has worked best for me over the years and I've seen a lot of tanks that have, in my opinion, been stocked way too early that barely last a year before a crash. Rome wasn't built in a day... but a day is all it took to bring it down.
How long has this tank been up and running? Newer setups go through some different algae growths even if you have relatively no bioload and great filtration.
Make a big step up in your cuc, keep doing weekly water changes and you'll probably be okay. Adding a protein skimmer will also be a very big help not too far down the road, because like I said earlier, Tangs have very high metabolisms and consequently produce a lot of metabolic wastes like ammonia. As they get bigger, and they will very quickly, you are going to have a very difficult time dealing with their waste (a lot of your corals won't be able to with it) even if you have a skimmer. Again, I hope I don't come off as rude, I'm (everyone else as well) just trying to help prevent you some major headaches down the road. Reefing is a game of patience and a battle between deficiency and excess (I stole that last part from Aristotle's "Nicomachean Ethics").