No, I was not incorrect.
I told the same thing: The surface of the area is what does makes a difference with evaporation. But there are many hydro systems that have a large surface area. The surface of water and the contact area with the surrounding air with a sprayers-system can be larger then eb & flow for example. Perhaps your waterfall system has a great watersurface, but perhaps someone elses watersurface and contact-surface with sprayers is bigger.
So waterfall in itself does not make a system better in this way for cooling.
By the way: That's interesting: "evaporative coming trades temperature for humidity"
You just invented a new physics law.
I did not say that cooling because of evaporation does not work. I even gave example that it does work.
Everybody who knows something about physics knows that.
But the heat has to go somewhere. Heat can not turn into humidity. In a greenhouse they suck the moist air + heat out. And when the moist air get's to a colder area or surface it turns into water. Then the temperature of the air will go down at that point. Perhaps that is what you meant.
But if you would not suck out the air, the heat would go up in the greenhouse.
So again: that is what I said... the heat of the water will go into the air and the air is actively cooled (or sucked out)
But my original point you are neglecting: A waterfall system might keep the temperature a bit lower.
But there are many hydro systems that have the same effect.
Just because of a waterfall it will not stay in the mid 70's. It does depend on the temperature of the air.
And if a waterfall could get the temperature down to mid 70's, other hydro systems could do that as well.
You made it look that only a waterfall system could prevent water for becoming to warm
I do agree with you that greenhouses don't use chillers. but most of them also don't use waterfalls.
They don't because they know it is not that important. Of course they don't want their water to be 85 the whole time.
Only cannabis growers do it, mostly because they don't understand physics ("colder water can hold more DO", which by itself is true, but still irrellevant). And yes, there are some diseases that love higher temeratures. True.
Aerating water is not that hard. Maximum DO is easy to achieve. Just run a pump every hour or half hour for 5 minutes in a basin and it's done. I have pics somewhere on this forum of the greenhouse where I go often. They just have a few huge basins. They don't measure temperatures, they do no active cooling (only the concrete floor of course) and they run no bubbles, sprayers, waterfalls, whatever.
Just a huge pump that mixes it all up every hour. That's all.
Low temperatures can prevent some diseases, but not all. Some diseases will thrive because of low temperatures.
People (not you) have a big misconception of the amount of DO water can hold and how it gets maximum DO.
