Help, acan is dying

[mcghee33]

I have a colony of acans that has been doing fantastic for over a year then all of sudden in the last 2 weeks he stopped opening up like he used to. Then i noticed a small white spot developing right in the center of him. So i tested my water and everything seems to be great, calcium is at 410, KH is 9, my salinity was a little low at 1.021 which has been corrected and nitrates were at 3 ppm. I did a water change since it had been 2 weeks since the last and performed an iodine dip and after the dip the white spot went away for a day and came back. So I dipped again. I am now religiously spot feeding cyclopeese and Rods food. Does anyone have any advice on how to nurse this acan back to health? Thanks in advance for any help

FYI the tank is a 75 gallon with 4 bulb T5 and the acan sits on the sand.

 

[mcghee33]

 

[RokleM]

Magnesium levels are...?

 

[mcghee33]

Not sure what my magnesium levels are, never have tested for it. I do bi-weekly water changes and every week I dose seachem buffer and calcium. I have had this coral for over a year and it started as a frag and never checked the magnesium levels and this has been one of best corals in my tank

 

[tritonman]

Nice sized colony. I would definitely check your Mg levels. You'll at least be able to identify the problem or rule it out.

I had problems keeping acans under my old LED tank. They would deflate and slowly recede. I saved the majority by fragging a healthy section, dipping in lugols, and placing in low light. If it continues to recede, that may be the only way to save it.

 

[reefer5060]

What color is the coral skeleton?

 

[mcghee33]

The coral skeleton on the bottom is white

 

[palyam]

my salinity was a little low at 1.021 which has been corrected QUOTE]

Could be the main reason, the most important factor

 

[mcghee33]

So my salinity is at 1.026 and never got dangerously low, I started dosing magnesium as directed here but I am seeing no improvement. I even went as far as to changing out my bulbs in my T5 to make sure there was not a spectrum shift that was upsetting the acan. I also have been doing weekly water changes instead of bi weekly water changes. My phosphates are still near non existence, my calcium is 410, my magnesium is 1300 ppm, temp at 79,alkalinity is 8. But my acan is showing no signs of getting any better. I am target feeding rods food wit addition cyclopes and DTs phytoplankton. Does any one have any other suggestions to get this acan back to good health????

 

[cjk76]

.005 is a big jump for salinity. I would stop dipping it as it is probably causing stress. The change in lighting could also be causing stress.
If it were my coral, I would shorten the photoperiod and keep feeding it. If it hasn't gotten any worse, it is probably getting better.

 

[pciscott]

When spot feeding Acans you can teach a lazy fish how to eat coral, hide and watch your tank for a hour and see if you have a fish nipping. Angels and File fish are the worst, but I have had several tangs that have got a taste for coral and had to be removed. I have a large purple tang that just got a taste for clam I am trying to catch. Your parameters sound good so I would suspect a fish or even a crab. Good luck.