mixture of dark GHA and slime.

[atoll]

My DIY ATS has a few types of algae growing on it it seems. Both are lit by my 20w LED';s but run more like 14w each.
first the front of the screen.
http://i541.photobucket.com/albums/gg378/lesmelling/Aquareef%20300/20150930_225055_zpstglhmrm1.jpg

Now the back of the screen.
http://i541.photobucket.com/albums/gg378/lesmelling/Aquareef%20300/20150930_225121%201_zpsdrln6uem.jpg

I have some slime with some very dark green short hair type algae underneath that. I clean the screen every 4 or 5 days.

[SantaMonica]

Just needs a good scraping. The yellow is over-lit, and the dark is under-lit.