Montipora dying

My tank is pretty new but has been doing well. I bought these two montipora frags back in july. While everything else in my tank is growing nicely, these two frags never seemed to get going and they really took a dive over the last month. I'm pretty sure they're done for but I was wondering if anyone had any ideas about why. I use a 4x54W T5HO. Here are my levels over the last few months.
NO2 -0
NH3 -0
PO4 <.04
Mg – 1200-1340
dKH – 7.7-9.1
Ca – 370-390
Thanks

 

are there any other corals in the tank? The PO4 number is concerning because that is just showing free phosphates. Generally phosphates are too bound up in algae to even show up on these tests.

 

I think I have been having a bit of a phosphate issue this week, for the first time since I got things started, but everything else seems to be doing fine. This picture is from 2 months ago. Everything in it has been growing except for the montipora.

 

If it has been slow, it sounds like lighting to me......what kind of fixture do you have. T5HO doesn't mean anything if your reflectors are substandard.

 

216W 48" Current USA Nova Extreme T5HO Lighting (2 10K, 2 460nm)

 

I think you photoshocked them with too much light and they lost their zooxanthellea and have never recovered. That beautiful clam is a good indicator you have enough light for monitpora.

 

crap...for some reason it was too small for me to see the clam. Yes I do agree. Too much light can do it as well. That's a pretty good fixture. Next time you get monties, start them on the bottom and work them up. Montipora is very tolerant of low light. BTW, that clam is gorgeous.

 

Thanks. I got extremely lucky and my friend gave it to me along as many zoa and mushroom covered rocks as I could carry. I've always wondered about whether I had the light right. The shelf montipora doesn't get as much direct light.

 

But I just remembered where I put it when I brought it home and I probably photoshocked the crap out of it then.

 

Agree with what's been stated. And I'm sorry to say, but those are definitely toast at this point; no tissue left.

What do you have for flow? I see a large powerhead in that picture in a smallish tank, so I'm guessing that's not an issue, but I didn't want to leave that stone unturned.