[sensei]

Originally Posted by Twinfallz

For what its worth, I've put some green scrubber algae in a zip lock bag, for a month, in darkness, and it stayed green.
I've also scraped off the excess algae on a screen I've decommissioned, left the screen sitting in the sunlight, dry, and the remaining base algae turned a pale creamy white colour - dead, after about seven days. When i've wet it, it turned soft and crumbly.

An illuminated dry screen seems the only logical answer.

Yes, it is the only logical explanation.
Thanks