Why do all that fussing when the res/valve system works so well?
Why ignore using the Autovalves and just fill the trays manually? A number of good reasons (for me):
1) It's simpler, less work, just partially fill trays vs. tending a reservoir, lines and Autovalves.
2) More control, particularly if, like me, you prefer coco have genuine wet-dry cycles, not endless wet-less wet cycles. I can feed a couple times a day or every few days, however I want.
3) I avoid messing with a reservoir and all its problems - feed going bad; shifting pH; lines getting blocked; concerns about spillage; etc.
4) Related to not using the reservoir, as I noted I can feed my plants organic supplements. For example, I normally feed at 2 mL/L AN Connoisseur base plus 2 mL/L AN Mother Earth Super Tea, BioBiz Bio-Bloom, AN Iguana Juice or other 'organic' type base nute product. And I can feed products, such as CarboLoad, that would ferment quickly in a reservoir. Even though all the various feeds and supplements are each claimed to be soluble and hydroponics-friendly, when you put them together and then environmental fungi and bacteria do their thing, I always got sedimentation and/or nasty fermentation with my AutoPot reservoir. I run the AirDomes at 2 L/min. each non-stop.
5) Save space, smaller footprint - no elevated reservoir needed.
6) More convenient: In a small tent with 8 AutoPots at all stages of growth, I have to mix multiple feeds. To use the AutoValves, I'd have to have multiple reservoirs for different feed mixtures.
Yes, the reservoir and AutoValves work well, but to me it seems like more work, complications, restrictions on feeding options, etc. Manual bottom-feeding obviously works. [Caution!] I don't think it works better than using the AutoValves. But I think it is comparable and a viable option.
