Dosing pumps - development discussion

[Skybound]

solenoid valves generally will only allow flow in one direction, but not the other. Plus also, they generally require 3 psi of fluid pressure to open. That particular water valve is only a 1/4" and most grows use 1/2" PVC or poly tubing. I spent well over a year looking for a solenoid/servo valve that is 1/2", does not require a certain threshold PSI, allows flow in either way like a ball valve and is plastic so not to ever pollute a reservoir with oxidized metals, but sadly the market does not yet have this. I bought a 3D printer and have been trying to design what I need, but so far am unable to print what I need that moves correctly and remains water tight. I’ve since expanded my grow and put this on the back burner for a few months.