For a bypass you simply install a tee after the pump. On one side you have your manifold, on the other, you use a ball valve to control excess flow back into the reservoir.
I had this happen on some bagseed before. They ended up turning white, then eventually orange. Even on nugz that I harvested when still pink, they were orange once dried.
Are you thinking about running all 8 tubes with individual reservoirs?
Or 4 each on 2 res? or all on one?
The problem with a perpetual style garden like this is that most of these systems use a single res for all of the tubes. Since you'll have several stages running that will require different...
The most common reason for cycling the pump is to combat the heat that it creates while running. You don't need a "drying out time" for aero, there is plenty of O2 available while the pump is running.
I hate continuous meters. The probes get dirty as hell sitting in nutrient solution all day(the proper storage medium is 0ppm water for tds and ph storage solution for ph). If you have multiple res's(or may upgrade later) you have to buy another meter. I do own Hanna meters, however and am...
You probably don't need to do anything more than dump out the old shit and add fresh water and nutes. A quick rinse isn't a bad idea, but unless you have an infection, you don't really need to do much "cleaning".
I use a huge pond air pump to aerate several reservoirs. It makes a shitload of noise. Vibration is the bulk of this. I hang it from the ceiling with a bungie cord.
I believe that chances are, if you heat the res, the tent will stay warm as well. I'd be more concerned with the size of the heater. How big is your res?
2 400 w lamps won't produce the foot print that you need. You'd have a rectangular pattern on a square area. The 600w would be better. If you can handle the heat, I'd go 1000w myself. The hood decides the pattern of light. You want to try to find one that produces a square pattern. I believe...