I thought the bright stuff was cyanobacteria.  I have had that in a previous tank and I could kill it with peroxide, but never totally get rid of it.  
Whatever I have is the same color as my green plants and Excel does seem to keep it in check. I was hoping to avoid CO2 if possible. Thanks for the info!
	
								Whatever I have is the same color as my green plants and Excel does seem to keep it in check. I was hoping to avoid CO2 if possible. Thanks for the info!
					
					
				
						
					