MB these are the vent openers I use.
This is the insulation I put up before winter to extend the season in side and start seeds earlier. The hobby greenhouse that came with has a pump, not faucets for the water (no hot of course), like I have in the fields.
Solar circulating fan is something like this but mine was cheaper.
This is the sort of high tunnel I am building now. I don’t like my round one.
In a former greenhouse with no running water I took a 55 gallon drum spray painted white, built a frame to hold it up in a corner with shelving below, drilled out and silicone caulked in a pvc spigot and attached a 6′ premade length of hose to it(I think was 5/8?). Filled it. Worked great.