Red Bubble Algae

I have a 30G that has it bad. I have been taking the rock out scrubbing the algae off and giving it a fresh water soak for about a minute or two. that gets it off the rock for a while. I have increased my emerald crab population in the tank too.
 
Is that helping?
Have you been able to identify exactly what it is?I have looked all over the net without any luck.
 
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