Could there be an option to change valves technology via config to something else than fluid control? I'm playing py mods right now. I would use those sweet valves right and left with amount of fluids I'm operating with, but getting "green science" is rather hard.
What I think is strange anyway is that there is no point of having valves once you have pumps researched. Maybe only if you don't have engine right on you and you want to set up something quickly or if you are very far away from power, but that happens very rarely. I wouldn't use valve where I could use pump and circuits, pumps with circuits use force to push and are more flexible, so I like them more.
I would suggest making valves available from steel research, tho valves don't even use steel, so maybe automation or no tech would be an option. If I recall correctly back in time valves needed no tech. Currently I will try to find it and change it in raw code and disable updates for this mod : / just so update won't revert back my tech requirement. If I knew more about factorio modding API I would write that option in and send you proposition to implement it but as for now I don't know how to add option in game menu.
Edit : Ok, in prototypes->recipes I just disabled "enabled=false" lines. Will see if it will work on old save. Aaaand it worked. Writing in case if somebody is interested in my solution. Oh, but I don't know what will happen if game will try to enable enabled technology. Possibly nothing wrong, but I don't recomend my solution. Perhaps I'll have recipes doubled or nothing will happen.
