Got any linkage to sellers with suitable pumps? My usual hydro shop doesn't deal in anything but the small aquarium type centrifs (400-800 litres/hour).

Very good point. My only concern past that is how easily fresh air can enter the area where the spraying is happening. If the misted area is well sealed, fresh air might not get in very efficiently. However, there's probably going to be enough air gap between the plants and the holes that they drop into in the PVC pipe to sort that out.

I think I'm going to build a very small (perhaps suiting 4-5 plants) 'proof of concept' model and grow out a few plants before going whole hog and replacing all my flood trays.

The design mogie has posted includes a filter on the water pump input, but I'm with you- I have some concerns about nute salts crystallising on the sprayer nozzle apertures, simply by virtue of exposure of the sprayed nute solution to air. This is a problem I contended with when I was using a drip system some years ago- and the main reason I switched to a very clog-proof flood system.

It seems sensible to fit the sprayers into the PVC pipe in some manner which is easy to disassemble and clean- perhaps by fitting rubber grommets to holes drilled into the PVC pipe, which the sprayers will fit tightly into, instead of mechanically fitting the sprayers more permanently though the pipe.

I'll tell you, I wouldn't mind eliminating the rockwool potstuffer media from my op. The used rockwool is easily disposable, but at the end of the day, I still have to buy it and get rid of it when I'm done with it.

I'd also like to eliminate the netpots and expanded clay from the featured design. I've seen some aero systems which support the plant without the need for any expanded clay pellets.

Another thing which occurs to me is that I really like the ability in the flood system to easily move plants around.

This is most important when I have to spray plants for powdery mildew, which still happens from time to time despite a dehumidifier, good air circulation via osc fans in each corner of the flowering area and more than sufficient air exchange capacity in intake and exhaust fans. It's convenient to be able to spin a plant around to make sure all of it gets throughly sprayed.

Seems to me that the plant will have to be in a netpot with pellets to make 'portability' of individual plants even remotely possible. I'd still be concerned about damaging those roots which would be hanging freely from the netpot, unsupported by any media, while lifting and turning the plants around to spray them.

duhhhhh....

mogie already covered that. wake up, Al..

Scratch the high-pressure pump idea. Lots of potential problems, now that I think about it.

I think I can produce a more finely atomised mist than with lawn spayers- and not have clogging problems- if I flood the PVC pipes and put a number of airstones in them, driving them with plain ol' diaphragm type aquarium air pumps, using several in a redundant arrangement.

The air bubbles breaking the surface of the water will create an acceptably fine, oxygenated mist- if the mist jumping up from my present aerated reservoirs is anything to go by.

However, the "airstones" (mine are not really stones, but rather tubes of a porous synthetic material with a stainless steel tube inside to weight them down), about 1" in diameter, would have to be submerged, at least under about 1" of water, to send up a good mist. If the PVC pipe is 6" dia, this leaves only 4" for roots to hang in mist. A larger diameter tube, perhaps an oval shaped tube (if it exists, 8" x 6" would be ideal) or a ~8" deep channel with a lid might be alternatives.

I might even be able to convert my existing flood trays to aero in this way. Running the pumps as they are floods the trays to about 3" deep. I could put airstones in continuously flooded trays and make a plastic cover with "pot holes" in it, suiting netpots with a little rockwool or perhaps clay pellets to cover the flood tray and trap the mist. If I used rockwool, I'd have to play with the aeration pump duty cycle to keep the stuff from saturating.

hmm...

Well, I guess I'll have another cone and think about it summore...

Fuct, use a utlity pump . The pressure these pumps put out is pretty strong, stronger then a regular house water pressure. I think it pumps about 250gph may not be necessary but im sure it will do the job. You can get them for 80 bucks at home depot i like to go with flotec. Also what you say using the garden sprayer the flotec would be awsome because that will imitate the water pressure from a garden hose. Hope that helps your pondaring I read alot of your post and your really helpful hope I helped you solve this matter.