Tree coral acting funny?

[arwentheelf24]

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:
pH: 8.0
Alk: between 1.7 and 2.8 (dont have a very accurate test for that yet)
Ammonia: .25
Nitrate: 20
Nitrite: .1
Calc: 560
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?

 

[Jimbo7]

The ammonia level is a bit iffy. How accurate is your test kit?
Do you test iodine before you dose it? Because thats my guess. Iodine is one of those elements that is usually replaced by PWC and there is no need to dose it. Its quite easy to poison your tank with it actually.
Make sure your new heater isnt swinging the temp around either.

Is anything else showing symptoms?

 

[melosu58]

You dont need to dose iodine. Your PWC`s will take care of any iodine needs you may need. Why are you adding purple up? That`s the reason your calcium is too high. Any amount of ammonia is lethal. Those are the problems I see that could be contributing to your tree corals health.