First off, be patient! I'd use urchins, sally lightfoot crabs and thin strip hermits. When ever the equilibrium of a tank is disturbed (changing nutirient levels certainly counts) nuisance algae is almost always going to be able to take advantage of the situation. Expect it to take several months for your corals to adjust and a new equilibrium to establish itself favoring corals over algae. Besides algae grazers I'd use manual removal with water changes and spot used of H2O2 in a syringe to reduce the algae.
Here's how I use steel straws to remove algae:
These video may help understand the complex relationships between corals, algae, sponges and microbial processes:
"Coral Reefs in the Microbial Seas" This video compliments Rohwer's book of the same title (Paper back is ~$20, Kindle is ~$10), both deal with the conflicting roles of the different types of DOC in reef ecosystems. While there is overlap bewteen his book and the video both have information not covered by the other and together give a broader view of the complex relationships found in reef ecosystems
Changing Seas - Mysterious Microbes
Nitrogen cycling in hte coral holobiont
BActeria and Sponges
Maintenance of Coral Reef Health (refferences at the end)
Optical Feedback Loop in Colorful Coral Bleaching
Richard Ross What's up with phosphate"