pink pom pom xenia not doing well

Sounds to me like your cooking him.
Leave the 2 250w MH's off and only run the actnic and daylights.
See how he does then

 

I wouldnt add salt. I would start topping off with saltwater slowly to raise the salinity to at least 1.025. You would need to check it after adding the top off water, just wait for and hour or so for it to get mixed in before testing. As mentioned before you may need to move it around til it finds a happy spot.

 

count your blessings. xenia won't survive in my tank either and I think it's due to lack of nutrients. It means you are doing a really good job of keeping your tank up.

 

I agree - also let them settle in a little and don't keep moving them around too much. I would try placing them in the mid area with a moderate flow and see what happens there only using the day's / actinic's. Once they start growing, there is no stopping these either!!! 8)