Shrimp seem to do equally well indoors or out. The mixed-cell raceways that have been built so far have all been inside greenhouse bays. The light is for the algae/bacteria in the water rather than for the shrimp, although nauplii (first larval stage) are attracted to light. That is how they are collected in hatcheries. Pacific white shrimp are egg scatterers. After a pair spawn they are removed. After the eggs hatch and the nauplii are motile the room lights are turned off and a light is shined on the surface where they are collected. My project will be indoors but well lit.

I again searched through algaescrubber.net archives after I posted my question and I found several references to allowing 1 in2 of substrate/gallon of tank water. However, I've also seen references to using the amount of food fed/day as the real criteria for sizing a scrubber's substrate. I don't know how to convert cubes/day to the way we feed shrimp, which can involve kilograms/day fed on a continuous basis with a spring powered belt feeder. Do you think that 1 in2 parameter is valid for food loads of the size I've mentioned?

I've searched the Internet for LED grow lights and those targeted at hydroponic growers are massive compared to light bars. The fixture builders seem to have embraced larger is better, 3w and 5w chips. Hanging the light two feet above a couple of MJ plants makes sense but 1-2 inches from an algae substrate seems like overkill. Those I've found don't seem suitable for the sort of up flow scrubbers I've read about here. Can you be specific with a recommendation of a light or a light supplier that has LEDs that are suitable for scrubbers?