Single IBC tote system pumps and filter

[Michael Garver Jr.]

I'm starting out small, with a single 30"x35"x47 FT and an 8"x 35"x47" GB. Hoping to build a system that can be built now and improved/ added to easily at another time. Because I don't know how big the system will get and how quickly (depending on overall success), I want to get a water pump that is sufficient for two more beds instead of a small one now and a bigger one later. What is the common rate of flow for systems of this range?

Another question is about the sump; how small can I go in relation to the FT and grow beds in a CHIFT PIST system? I think I have ruled out the need of a spin filter for the simple fact that the grow medium is probably filter enough. Should I go ahead and build one anyway so I don't have to worry about it later?