Thanks for the reply Mindy.
After doing some tests on the water that the rock came from, I'm a little hesitant about putting this rock in my display even after several weeks. I tested for phosphate, nitrite, and nitrate, and they were all almost unmeasurable. He had new bulbs in his tank, only 4 fish (its a 65 gallon), and its downstairs out of direct sunlight. In addition, he said he did water changes every 2 weeks. When I was picking the rock up, he asked me why I thought he had the algae problem. I thought his problem was phosphate, and maybe it is, and I only have a cheap test kit that just tests the water column, and I don't think he was using a phosphate remover or ro/di. So, do you or does anyone on Canreef think I should be skeptical about putting this rock into my display even after I "cook" it?