Yes, it's removable, and anyone can grow red turf. It is a solid flow (not the trickle you get with the GHA scrubbers). And the proper light with a proper photo period. The screen is a black two ply screen. It is not the hobby lobby white stuff you rough up.
In this design, 30% of the drain water is dumped behind the screen in a chamber, the screen is at a slight angle and the water rushes over it, the other 70% of the water is dumped into the large chamber of the sump. I am running a MAG 9.5 on the system and no restriction on the pump, other than a 30" head.
You can buy seeded screens to shorten the process.
If you want to know more about true ATScrubbers, PM me.