Acan Coral Shrinking

[Nolan99]

I have this acan frag that I have had for about a month. I am a beginner reefer. I have noticed that it seems to be growing in one of the polyps, but this one polyp in the front has shrunk or moved from the frag/rock. Can you explain what this is? My lighting is two T5 55 watt bulbs. They are bulbs that have regular light and actinic. (If it helps it came with the Red Sea Max 130C). The bulbs are about 5 months old. Here are my water parameters:
Temperature: 78.5 degrees F
Salinity: 1.024
pH: 8.0
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: 0 ppm
Calcium: 340 ppm
Alkalinity: 9-10 degrees dKH
Phosphate: .25 ppm
Magnesium: 1170 ppm
Dissolved Oxygen: 7 ppm
I was wondering if it could be losing its structure maybe because the calcium is so low, along with magnesium, and the pH. It is 5 inches from the bottom and I can’t really tell how much flow it is getting. I’d say it is probably getting good flow. Also, to get the calcium up, along with magnesium and the pH, could I just add Kalkwasser to my ATO? Thanks for all the help!

 

[Sniperhank]

Are there any tubes nearby? It looks like the web from vermetid snails causing the recession in tissue.

 

[Nolan99]

Are there any tubes nearby? It looks like the web from vermetid snails causing the recession in tissue.

What do you mean by tubes? I don't think there are any of these tubes or snails in the tank. I do have these feather dusters that I was told were harmless.

 

[Sniperhank]

Hard tubes coming out of the rocks. Do you see any 'web' in the tank?

 

[Nolan99]

Hard tubes coming out of the rocks. Do you see any 'web' in the tank?

There is a web of all these tubes but they are connected to these feather dusters on the ends. Otherwise the only thing I could say is I have seen a worm before moving around in that area. In the sand bed it also looks as if worms may have been there.

 

[Sniperhank]

Then those aren't feather dusters if they are throwing out webs to filter feed. Those would be vermetid snails.
Take a picture so we can be sure.
That worm though will be a part of your clean up crew and eats dying tissue.

 

[Nolan99]

Then those aren't feather dusters if they are throwing out webs to filter feed. Those would be vermetid snails.
Take a picture so we can be sure.
That worm though will be a part of your clean up crew and eats dying tissue.

Here are a few pictures. When you said web I thought you meant by the tubes all along the rock. They aren't actually sending out webs into the water. Do you really think it could be something eating the scan, or is it possible the calcium levels are causing it to shrink? I'm a newbie, but the other side of the coral seems to be growing, so I am a little confused!

 

[Sniperhank]

It is being irritated by something... What are your current parameters?

 

[Nolan99]

It is being irritated by something... What are your current parameters?

The parameters are in the original post.

 

[Sniperhank]

How were they acclimated to the tank? Hows the lighting over the tank?

 

[Nolan99]

I put them in coral rx, the Zoas I have are fine. The lighting is two dual T5 55 watt bulbs that have an actinic side and regular lighting side for each bulb.

 

[Nolan99]

How were they acclimated to the tank? Hows the lighting over the tank?

The guy at the LFS said I didn't need to acclimate them. The coral has been in the tank for a month now.

 

[Nolan99]

One polyp on the right has healed from the fragging, but this one on the left has shrunk. Could it be moving off the rock? I don't know if that is possible. Could the parameters have anything to do with this? Please help!