IMO and IME Euphyllia corals prefer to be in lower light and lower flow. They can take med light but really need lower flow to allow them to open up all the way. Check out my thread located in the LPS forum its called New Additions.
http://reefcentral.com/forums/showthread.php?t=2540376
Also best sg is 1.025-1.026. Need to also know your Alk/Ca/Mg parameters. I believe you're getting a false 0 on nitrates having the algae you have in your tank and yes your phosphates are way too high.
What salt mix do you use? Need the Big 3 parameters if you don't have test kits you need to invest in them.
Can you take a full tank picture to post?