Indoor soil storage/ composting

I'm going back over to soil after doing hydro for the last 2 years. Last time I ran soil I lost everything to a combined gnat/ aphid infestation. I'm pretty sure it's because I was bringing in soil from my outdoor compost piles. This new dirt is never leaving my basement, gonna use, amend, cook, reuse, etc, etc.

So, how do you manage your soil indoors? I figure I'll be rotating something like 100-125gals of soil total, running about 50-60gal at any time, so say 50-60 gal in reserve being amended/ composting. Every 5 weeks I'll be pulling 25 gals of amended and adding 25 gals of used soil. Right now I'm using a 54 gal tote, but I'm going to need something larger, maybe 100gal size and more HD, I've almost put my shovel through this thing a couple times. I'm in a basement, so space management is also a concern.

I have my neighbor who deals in used kitchen equipment keeping an eye out for an old, junky commercial dough mixer, but I think that's gonna be overkill... cool, but overkill.

I used to use a cement mixer, in a barn, with plastic pools lined up.
then I learned I could use brand new pro mix every time instead and amend with organicare ferts .
I recycle the used fertile dirt in my greenhouses and outdoor gardens.