algae problem in my nano reef

[theexoticbichir]

I started a reef about 6 months ago and my parameters were in the green until about a month ago when i got a horrible outbreak of green hair algae. This algae has also started to grow on my zoa's therefore killing some of them. I do regular weekly water changes and I run a refugium and a protein skimmer but my two turbo snails died mysteriously (probably the pistol shrimp). I was wondering if I should introduce emerald crabs or sea urchins because I am hopefully upgrading to a 20 gallon long.