Why are my montiporas not growing?

[Tbg299]

All of my other sps frags (stylophora and seriatapora) are growing except my Montis. I have a Sunburst montipora (plating) and rainbow montipora (encrusting). All of my parameters are in range for sps, and they are receiving the same flow and lighting. Honestly don't know what the problem is. If anyone could give me some more information about montiporas it would be highly appreciated.

 

[blaxsun]

An image or two probably wouldn't hurt.