There are very few 2" PVC solenoid valves that can survive salt water corrosion. I only found one and it was ~$500 each.
Pool valves work but are very slow and they’re expensive too ~$400 and they need +24V/-24V just like my actuators do (+12V/-12V)
My setup cost ~$80 per valve, most of which was $50 for the linear actuator, which is now $35…
At two valves, it was $160 vs $1000! Now it’s $130 vs $1000 for the next two.