I'm going to plumb in some extra sacs, take my rear tanks out and replace with sacs in my 2004 SAN which has the aerator pumps with basically 0 PSI. I currently have cable actuated valves from Flow Rite which work OK, but tend to leak a bit so I was searching around to see if could find any other options. I did a search for gravity flow solenoid valves and came across this:
https://www.adafruit.com/products/996
The ports are 1/2" NPT so not ideal, but since my boat has scupper intakes that fill without pumps while driving, it might work out OK. I just ordered 1 valve to check it out as I couldn't find an answer on the web site as to how big of orifice it had for flow. Nice thing is 0 PSI required to operate so this could be useful to others regarding any ballast system plumbing.
Has anyone else tried these valves? I did a search of the site but didn't find anything.