Thought I would give this a try

[ktsdad]

No evidence of growth on my screen after 7 days. :cry:

Since my screen material is not rigid, it sags between my frame support therefore the water doesn't flow across very much screen.

I saw some egg crate type material (PVC) that I am going to get today.
That would support my screen material evenly across the entire surface.
My hopes would be better water distribution.

I will post a picture of the new screen once I get it built.

[SantaMonica]

Well your screen material is green, so it's harder to see initial growth. Feel it and see if it's slippery.

Egg crate will help, for sure. But with those strong lights, you are definitely going to get growth no matter what flow you have.