While the Spore Vent is intended to control the release of the fluid spores created from cultivation (and release fewer than breaking and replacing pipes, tanks, etc), if any mods add ways to void fluids, such as Maraxsis's Hydro plant, then it becomes possible to bypass this system by voiding the spores in a machine that doesn't release pollution on Gleba. Since the cultivation recipes don't produce any regular spores, this would allow for zero-pollution farms.

This is true. For this reason, steps have been taken to keep the Spores fluid on Gleba - it cannot be barreled. However if anyone wishes to play with a mod that results in this exploit, and then they go and use that exploit then there is not much I can do for that person. This mod is designed around the balance of the base game, and with the base game there is no way to void fluids.

I can only hope that Miraxsis's Hydroplant isn't buildable on Gleba! haha (It looks like a fun mod too!)