Please help my hammer coral!

I've noticed when my Ca is a little low, my pink hammer usually doesn't have much tentacle extension.

 

The parameters for my tank are as follows:
Calcium - 500
Phosphate - .05
Nitrate - 0
Ammonia - .1

My ammonia is a little high but usually runs 0
I tested my Iodine again as I don't test all the time. I did a partial water change today (about 5 gallons) and the iodine was very low. Around (.02).
I usually add about a half teaspoon about every other week but this may not be enough appaerently.
I will post a pick ASAP.

 

Almost forgot -
Specific Gravity 1.025
Temp 76 - 78 deg F

 

.1 ammonia is not bad. when you say iodine do you mean your salinity?

 

Medium flow - just enough to move the tentacles slightly.

 

This number is from iodine/iodide test

 

got it I never tested for iodine sorry I don't know what's good or bad reading.

 

According to what I have read a (.06) is NSW. Thats why I would say mine was a little low.

 

Here is the pic of my hammer coral. Sorry not a very good camera.

 

magnesium is also an important parameter for LPS corals. you should be testing this as well. They can get temperamental if mag drops below 1200 I have found.

imo I think the hammer is getting a little too much light and or too much flow. I have my hammers and frogspawns near the sides of my tank low on a rock because they absolutely hate flow. They need flow that is just enough to move their polyps around softly. anything more than that and they close up. i would try moving it down and see what happens.