Help with Duncan coral

[rpc07]

My Duncan has been like this the past 2 days the only thing that has changed in my system since then is I replaced the purigen. It's possible I didn't rinse it well enough. All my other corals are open and colorful as usual.






Any help is appreciated.

 

[lynchmob3000]

It may need to be rinsed better, or its stripping to much nutrient ****ing the Duncan off