This got me thinking, I will need to set up a reservior and float valve to keep the level constant. Because when the solution drops it sets a new level standard. It would be a pain to fill it daily by hand.
I have been thinking about a watering system where I have one large water reservoir bucket with a fill line going down to any number of planters with individual float values on each planter. Each individual planter would draw water as needed from the reservoir bucket when the float value opens. That would allow a person to set different levels on different planters.
Another setup involves a water control bucket with a float value set at a certain height, and having all the planters on that same level. Since water will seek it's level in that system, each planter and the reservoir would have the same height. That involves only one float value for the main water control supply. You could supply water to the float valve on the control bucket from a much larger water reservoir bucket probably above the height of the control bucket.
Someday I'd love to get into hydroponics. I would love to grow food indoors in the winter where I live in northern Minnesota. The Kratky system sure looks interesting. But I would have to rig up water lines to keep the fluid at my desired level because I don't want to have to water stuff daily, either.