Need help identifying weird growth in sump

[Kth]

This red-ish stuff is growing in only one compartment in my sump. There are lots of little critters that are hanging on to it but not eating it. I get about this much build up in about 9 days. It grows no where else. The next chamber gets the same lighting and has none of this growth, chaeto, and dragons breath grows in the second compartment. The chamber before it has a protein skimmer.

 

[Big G]

sponge?

 

[Kth]

sponge?

It seems to grow far too quickly to be a sponge.. & there are lots of air-bubbles. Also, its definitely photosynthetic.

 

[Kth]

Here are photos with flash and fuge light off. This stuff first showed up approx 6-9 months ago. I clean it out every week and a half. the second picture is the next chamber. There isn't even a hint of any algae or bacterial bloom in the display tank, and all my lps, sps, anemone are healthy. I only have three fish in the tank.

 

[Big G]

Check out this link: http://images.google.com/imgres?img...104&prev=/images?q=pink+algae&hl=en&sa=X&um=1