Algae and glass tops

Talking about duckweek growing in some tanks and not others brought up another question for me.  I am doing weekly maintenance today and have some of my tanks with SERIOUS, nasty, stinky, algae growing on the glass top.
All my tanks have the exact same lights and the same glass tops.  They all have a certain amount of "splash" from the filters.  However, some of these tanks are absolutely covered with what appears to be BGA and others have none.  
Yes, some of my tanks DO have some BGA growing in them BUT it is not necessarily in the ones that have it growing on the glass lids.  I use the scoop it out and syphon it up method of removal in the tanks, unless it gets out of control and then I hit it with some Excel and that works great until it comes back.
I notice the awful smell when these algae covered tops are opened, but the good news, it hoses right off with the spray from my kitchen sink, and then I wipe down the cover and it's good for another week.
Any ideas why some grow it and others never do???
Photo of one of the not so bad lids.

My lids also grow this stuff, although I don't find it as easy to remove as you stated. Might be that I also have the hard water residue helping it to cling to the glass. I find it grows over the spot where all the bubbles are bursting through the surface of the water from either the filter or the bubbler.

Yup. that is exactly where it grows best! But, they all don't grow it, which drives me crazy trying to figure out why!!!!

Oooh. Thats BGA growing where it is high humidity ! I get purple on the downpour from my HOB filters on some tanks. Definitely weekly maintenance to keep them under control.