Otocinclus! I added 3 more to my tank, and my tank is sparkling clean. So much so, that I have to start farming algae in another tank to keep them from starving. Before that, I had trouble seeing my fish through the brown haze. They're peaceful, and only get to be about 1.5 to 2 inches long.
Just a word of warning, they are sensitive to water parameters, and require an established tank and good acclimation procedures. Even with this, I still lost one.
If you just want to get rid of algae, and are unwilling to continue with the long-term care of oto's (they can be difficult to keep), however, just keep your tank clean. It's probably an overabundance of nutrients from fish food and poop that's causing blooms.
I was also going to suggest keeping live plants to outcompete the algae, but it looks like you already have some. Do everything you can to keep your plants healthy, and they should out-do the algae. I'm still learning about all this stuff, too. But the plants and the oto's definitely helped.