Thx for the replies guys! Plating algae is hard, this stuff is soft and rubbery. Its "leaves are flat" so it wont be bubble algae either. I had a fella pm suggesting its lobophora, something I'm gonna have to contain before its an issue. Link below shows a couple examples in the last row of pics. They can vary in color even though they are considered brown algae.
http://www.wetwebmedia.com/trialalgaeid.htm