euphlyia death

I have a SUPER tiny hammer coral. Its starting to have some tissue recession between the heads. it only has two heads and up until about a week ago the tissue between the heads went all the way down and connected. Now the tissue is receding back to where it only has tissue on each individual...

I am having huge problems in my tank as of recent and am trying to figure this out and rule it out as a problem. I have a Tunze 9001 in my Waterbox Cube 20. The only way to use this skimmer is to put the skimmer facing sideways and the magnet is being submerged in the water. I was wondering if...