Is my monti growing?

[Lt.Shineysides]

I have what i think is a pokerstar monti. Its got a purple/blue base and bright green polyps. I have it in a 20 gallon tank under 3 panorama leds. i was told that 2 of these would be plenty for a tank that size. It is pretty high up in the tank and gets good flow, but i noticed some of the tips are starting to look white. is this it growing? or is it dying? any adice would be greatly appreciated.

 

[aurora]

Most Montipora will have a white growth rim. You can see it better under actinics. Actually, I use my orange Monti Cap as a guage for my tank health since it's usually the fastest growing thing in my tank. If I see the white rim disappears or fades, I check my parameters.

 

[Lt.Shineysides]

okay, so is it only around the lip or edge of the coral that turns white? and thanks for the reply.