Finally I find a place where I can join a debate I'm trying to have for who knows how long. Yeeeey!!
I'm on my first RDWC run with new system developed in the UK.. Way cooler than UC ... imho... Google Alien Hydroponic if you're interested. Anyway, back to this debate, I eager to ditch the airpumps too. Here are my findings that I hope people comment on. I'm new to RDWC, did my homework, but still lots to learn.
Ok, so as far as I know, the best, most effective and energy efficient way to increase DO is through vortex, then fluming (or flooming), then venturi, then waterfall, lastly airpump.
Vortex;
Way to complicated to adapt to RDWC. Must be made constructed from scratch.
Fluming/Flooming
My favorite. Problem is root ball will quickly block the necessary bulge at the water surface.
Venturi;
The problem with venturi using a powerheard 135gph (500LPH)... I know its not alot, but was testing... is that;
a) passive air intake = unfiltered, extremely poor performance, and the venturi nozzle has to be very near the surface or the water pressure just a few inches under water will stop sucking air... I cant understand why though.
b) active air intake = bubble heaven, super performance, but uses the damn airpump.
Waterfall
Same problem as fluming, though I have some thoughts. First though, is the notion of DO. I cannot for the life of me find actual data on how long H20 is able to hold water once it has been saturated. I only have one anecdotal "paper" that suggests 24h, but a quick look into vortex brewing kits on youtube showed decreaase from 8ppm down to 7ppm in seconds when the vortex stopped. Now maybe this is just a sudden drop until "stabler" saturation that holds for longer... i dont know I would appreciate schooling.
Another is the 1 foot "mandatory" drop to create splash and induce oxygen transfer. I find no actual evidence for this, please point me to it. I mean, a big hose dumping a big volume, sure, big height needed, big splash needed. Makes sense.
But what if you split that huge diameter into multiple smaller ones with something like this;
(forget the rest, look at the "top wash device" thing)... I've seen them around in shops, dont know the actual name.
If DO is at good level with the dynamic nature of RDWC, what you really need is a maximum quality of nutrient mix n' flow, which is a problem mid/late flowering.
My idea is to have a big main recirc inline pump (included with the RDWC kit) and ditch the airpump for little 4w (or less) powerheads in each site. We could have a regular powerhead with one of these sucking the nutrient mix from the bottom of each site to the top, through the "top wash thing", pointed to the SIDE of the bucket, not the netpot or the surface.
Because if one can effectively increase DO somewhat and maintain it with a good flow, that is more than enough for mega yields. The rest is a proper green thumb. There is no "real" need to reach the theoretical 9ppm @ 19ºC (66ºF) except if root disease strikes.
But, since its a much smaller flow out of each little hole. then the splashing aginst the side of the bucket, netpot height, would create
a) highly increased TOTAL water volume surface area "affected". No need for 1 foot fall, in fact the less distance to the bucket the stronger the surface tension disruption = less noise
b) massive surface tension disruption = massive DO saturation anyways!
c) independent of root mass size
d) gzillion water splashes will increase RH inside the bucket, making baby rootlings explode
The only real issue is preventing the intake of the powerhead from clogging when the root mass gets massive. That can be a problem, but one that I am happy to tackle if I can shut up the damn airpump.
Going to try this next run, currently have both my systems 2 weeks into 12/12 and dont want to mess with them right now, they had a troublesome veg.
Did that make any sense? What do you think?
.
