This idea came to fruition late last night, someone posted on my build thread on AA that since the algae grows 3D so well in an enclosed box that is flooded, why not flood the entire box? Well as I was typing and describing that if the box was full, the water would have to enter from the slot tube at the top, then exit at the top, and water would stagnate and the algae would die. Therefore, the only way to make a totally flooded box work would be to have the water enter at the bottom of the box and exit out the top, and to my knowledge this had not been attempted.
Then it hit me - this would be the perfect design to work in combination with a tuned pipe overflow (full siphon - herbie or beananimal).
So riddle me this - would this design be feasible?
What I envision is something along these lines: You would have to have a watertight acrylic box with a bulkhead of some sort on the bottom of one of the sides, and this is where the full siphon would enter. Due to the high level of flow from this, there would be no slot tube to hold the screen. You could secure the screen in place by another method which I've got floating around in my head but it hasn't quite landed yet. Something to do with magnets and zip ties. The water would fill up the box from the bottom and would then have to exit out the top, either by way of another bulkhead or a spillway or sorts, or both as a failsafe to prevent clogging and overflow.
The difficult thing to figure out will be the lighting. Obviously if you're going to all this trouble, T5HO fixtures would seem like a logical option, but care would have to be taken to not mix water and electricity because they are not happy together.
The advantages I see are that you don't have to deal with a slot tube, spray, clogging, detaching and re-attaching the screen during cleaning, etc.
The disadvantages are that it is not very DIY-able, there is more risk, there is not an opportunity for cooling/oxygenation since the screen is underwater, and starting the screen from scratch may involve a different process.
But it's an idea. What do you think?
EDIT: I did think of a flaw. Getting the siphon to start with a tuned pipe could be problematic, because the pipe would essentially be several inches underwater, making it difficult for the full siphon pipe to purge all the air. Hmmmmm...