Acans don't do well in my tank...help me

Hey guys. Acans are one of my favorite corals and they look so nice. However, for some reason they don't do well in my tank. I have tried 5-6 different kinds. At the LFS they look really big, but when I bring them home they start to shrivel up and eventually die.

I put them on the sand or in shaded places where there isn't too much flow. I don't spot feed, I just put some reef chili in the current. I have a 75 gallon. Used to have T5's, I just upgraded to 2 Radions running at 50% peak hours.

Calcium:450
Alk: 8
MG: 1300-1400

Here's a few pics of the acans I currently have, the last one is probably dead.
What am I doing wrong? Is my flow too high? (running almost full power on MP40 on reef crest mode) Should I dip the corals after buying them? Should I try to spot feed?

 

Maybe try spot feeding them.

 

I try doing that, but I never see their feeding tentacles, not even at night. I am gonna try putting some food next to it and wait until it sticks to the acan.

 

Turn off the flow and drop the food in each head for starters. If they are in full shade you may need to get them in the light.

 

I will try doing that. What do you recommend to feed them? I have reef chili and zooplex

 

brine shrimp, mysis shrimp, small cut bits of fish and blood worms and also most tanks have fire worms that live in the sand they don't mean to hurt the coral but at night they will come out on top of the coral and irratate the coral pick the acans up and look under neath if there are worms attacted to the bottom remove them and the coral will open up again

 

Mysis and meatier foods like that.

 

Meat give them meat and get some sun on them

 

Blast them hard with a turkey baster. Stir sand before wait a few minutes the should open them boom blast them hard