Your nitrates are too high for most SPS to thrive.. I would start with doing some consecutive water changes to bring down N03/P04.. . What is your P04 reading? What is your fitration?nutrient export?If your nitrates are that high and you are dealing with a algae outbreak I'm betting your P04 is also high..
There is a lot to say to keep SPS happy. And from the looks of the Pic yours is not happy at all. It takes good water, good random flow, a lot of light,well established tank and husbandry and most of all good test kits.. If I were you I would spend some time in the SPS and reef chemistry and new to the hobby( even if you arent it breaks stuff down clearly)stickies and read and learn all you can to have the knowledge to keep more sensitive corals. Good luck and read read read.. Everything you asked Has been laid out in the stickies.. And asked 100's of times on this forum with hundreds of great responses so search and you shall find. Good luck.