How can I kill this bacterial mat?

[Just John]

I guess it would be called a bacterial mat. This is growing in the sand in a small area of the established tank and in a lot of corals. It doesn't appear to be a sponge. The gravel in this picture feels sort of like rubber with sand in it. I don't have fish in the tank, but feed Reef-Roids once a week. I have to dose daily for nitrogen and phosphate, so if anything they may get low sometimes. What can I do?
Current conditions:
Nit - 2
Phos - 0.04
pH - 8.1
Alk - 7

 

[KrisReef]

A tunicate, a sponge, a bryozoan???

I am skeptical that bacteria can form a structure like this one.

I don’t have a tested solution but perhaps a UV wand would disrupt this?

 

[Just John]

A tunicate, a sponge, a bryozoan???

I am skeptical that bacteria can form a structure like this one.

I don’t have a tested solution but perhaps a UV wand would disrupt this?

I'm not sure exactly what it is. Getting it off of a frag is difficult. It's like trying to scrape away a blob of jelly with a toothpick - the scraping tool goes through the blob, but it doesn't really do much to it. That's what made me think bacteria.

 

[KrisReef]

I'm not sure exactly what it is. Getting it off of a frag is difficult. It's like trying to scrape away a blob of jelly with a toothpick - the scraping tool goes through the blob, but it doesn't really do much to it. That's what made me think bacteria.

Hopefully someone else who has seen this can provide a better explanation and provide a prognosis for how to proceed!

Bumping up for other folks to explain