Basically you've got a very young tank. Most wouldn't consider it out of it's cycle yet, and you're feeding concentrated foods, (phytoplex, or whatever phyto product you're using), and using additives that are designed to encourage algae growth. You're also adding energy to the system by way of the lights. I'd suggest that the fact that since you have readable levels of nitrites, that you haven't finished your cycle yet. Normally I'd just tell you that you haven't finished your cycle, and that you need to turn the lights off and stop feeding the tank ANYTHING. Since you've already stocked the tank, I'd leave your lights as is, and go ahead and feed flake for the fish.. I'd stop adding phyto, coral builder, purple up, or anything else for that matter for the next 6-8wks. This won't hurt anything at all, but it will seriously decrease the levels of nutrients available for algae, and it will give your beneficial bacteria cultures time to grow. After this time period start back on your additives, but start slowly. All of those additives are really designed for larger tanks. Use half of what you've been using for 6-8wks, and monitor the algae levels. If at the end of that time period you haven't had any algae blooms increase it up to the levels you have been using.
In the meantime if they're at your LFS, you might try a couple scarlet legged hermits, and a couple turbo snails. Turbos aren't my favorite, as they're large enough to knock stuff over, but you can always return them after they've helped clean up your current problem.
You definitely don't want this to get out of control. People have had to strip their tanks and start all over because they've lost the battle to algae. However if you simply take away it's energy sources before it really gets out of hand it should be a quick fix.
Good luck,
B