Brown algae result of water flow?

As of late I changed my water flow: I removed the spray bar (didnt like the way it looked) and let the outlet hit the surface of the water. Also i put a powerhead along the back of the tank. About a week after I started to get brown algea on the gravel, LR, and glass....not much though..just enough to annoy me!! Is it a result of the change in water flow or something else.
Thoughts and ideas apperciated!!

All readings are 0's. P.H is 8.2, calcium 425. Lighting is 1 40w 50/50 and 1 40w trichromatic. Trying to grow more coralline........Tank is a year old. But now that I'm thinking...... I did make some other changes in the tank: removed bioballs and went with sump (two months ago), switched from reef carbon to Cuprasorb. Could any additives be a contributor to the brown algae? (Buffer, iodine,)
Thanks for your help.....