I have been out of the planted tank hobby for many years and am in the process of setting up a 205g tank (36"x44"x30"). I plan to start a separate build thread shortly also. After reading quite a bit of this forum it seems like one of my main challenges will be dissolving enough CO2 into 205g + ~50g of sump water. It seems like some guys that started out with 2" diameter Grigg reactors upgraded to larger diameter reactors to be able to dissolve more CO2. I picked up a really nice Matheson dual stage regulator and Ideal needle valve I plan to run on this reactor through my return plumbing. The reactor is make out of 4" diameter PVC with a small clear section so I can see what's going on inside and is a total of 28" tall. I guess I will need to run 5-10 bps on this tank. I have no experience with Grigg style reactors and would love some opinions and thoughts on this setup. I figure if I have to I can always add another reactor (but went big from the beginning and hoping this one can handle it).