What are you using to measure salinity? Your salinity is a bit high at 1.028. I shoot for 1.025.

Why are you convinced that your calcium is being depleted at a fast rate? 350 is not a bad place to be on calcium given your current demand (a few softies).

Just try adding a little iodine to see how the xenia respond. That should open them up for you.

Coraline will take some time to start covering surfaces. Someday you'll be cursing it while you scrape. Patience....