I have a 75 gallon saltwater tank that has a mated pair of percula clowns, a royal gramma, red starfish, 6 blue green cromis, a banggai cardinal, 2 peppermint shrimp, and a cleaner shrimp, 2 tree corals, a bubble coral, a cabbage coral and "waving hands" coral, as well as several small crabs. I do a 20 gallon water change every other week, add iodide once a week, purple up once a week and just started using marine snow.
One of the tree corals has not been opening to its full beauty for a few days now; it stays almost completely drawn in. It has been doing great up to this point (had it for about 3 months). Also, my calcium levels seem a bit high.
Prior to the tree not opening, I had recently put in a heater. The current temp of the tank is 82.
This weeks test results:
: between 1.7 and 2.8 (dont have a very accurate test for that yet)
Spec. grav.: 1.023
I use Red Sea Marine test kit. 20 gallon sump. Octopus protein skimmer.
What is wrong with my tank? How do I fix it?