I am in the process of building an indoor hydroponics controller and am trying to build the plumbing aspect of it. In the attached picture (.png), I have illustrated locations that I need valves to manage the flow of my nutrient solution or originating water. The plumbing circuit begins at the source reservoir that is topped of via a float valve. From there, fresh water is either pumped to Site A, or Site B. The size pump in each of the reservoirs is 160 gallons per hour that is capable of 2.0 PSI. Once this water is in either of the Sites, nutrient solution is mixed and and fed to the respective plant(s) for a specified amount of time in days or weeks, then that mixture is discarded via Waste Out. Periodic testing of the nutrient composition will be performed by pumping solution from a respective Site out the Test line and through a manifold of meters, and returned to that Site from which it came.
That said, I'll soon be in the market for cheap solenoid valves. The desired ones sold at Adafruit for $7, require a minimum of 3 PSI, and I've found that most of the needed plastic valves require 3 or more PSI to function, or the price is just too steep for my liking. Because this is a system that feeds plants, no metals can be used in the circuit so I am confined to plastic or stainless steel which is highly expensive. Does anyone have any leads on cheap plastic solenoid valves? The only other viable idea I have is to connect servos to PVC valves, but if possible, I prefer solenoid valves that are affordable and usable.
TYIA
