Beans need a fairly strong nutrient, µS-range 1600 - 2200 @ pH levels around 6.3.

I flood early in the morning, but no longer than ± 15 minutes. During very hot days I dilute the nutrient down to the 1600 µS-range and do an extra flood around 1PM.

I dont use an airstone. The flooding itself brings air into the nutrient, although some extra aeration is always good.

I pump 16 hrs/day, so there is a wide range of flooding intervals.

Keep notes daily and you will find out what works best for what you grow.

when using coco you should hand feed untill the roots are good and established. Then you shouldnt need to flood more than 2 times a day. Especially when the plants are still young. If you use only coco, with no perlite you should be able to flood only once a day.

This is what makes coco so good, it holds water better than most other stuff, and the air capacity is some 30% or so. You can use smaller than average pots and feed more often, and have more plants too...

once is more than enough water to keep your plants happy for a day. I grow about 2 ft tomato plants 2ft basil and lots of full grown Dandelions in Coco and I only top feed it for one minute a day with no problem.

Now if once a day is the best way to go for optimal groth, I can not answer that as I don't have the exp.

Good luck

Basketmaker, how did the bean growing experiment work? I am in the process of setting up an aquaponics system, which uses fish wastes for nutrients instead of nutrient solutions, and uses the plants to clean up the water for the fish. I'm wondering if the beans will pollinate themselves in an indoor growing environment or if they need pollination by insects.