Help!! Advice? Has anybody ran into this?

Lately I've noticed some dark blotches appearing on my live rock. I've got the rock in my 55 gal. I'm getting ready to upgrade into a 120 gal. I'm thinking I may have to start fresh with new live rock if I'm unable to eliminate this. Does anybody know what this is and/or how to deal with this? Some research I've done is possibly pointing at Lobophora???? Here are some pictures of what it looks like. These are not of my current rock but instead of pictures I've found on the net that look like what I'm dealing with. Thanks!

 

It is very hard. Similar to coralline. You can't scratch or scrape it off the rock with a brush or anything. You would have to scrape off the top layer of rock to remove it.

 

Don't know if this helps or not but the tank is about 2 years old now. My rock looks very similar to picture 3 that has a good growth of purple coralline algae established on the rock. In a way I hope it is brown coralline and yet I don't! It's not very attractive... I'm thinking I may take a single rock out and spot treat the brown areas with 3% hydrogen peroxide. See if that puts a dent in it. I would just like to get this sorted out before I start to make my move to the 120. Thank you everybody for your responses. I value all of them. Keep them coming!!

 

Ok so I'm really convinced it's Lobophora (aka Brown Wafer Algae). Has anybody had this particular algae?

 

That's what I was just reading on the Naso as well. I may give that a try.

 

I still haven't 100% confirmed that it is in fact Lobophora. It seems like a good candidate however I'm not ruling out what DangerJ and Bud said too.

 

Here is a picture of it on a rock in my tank.