small space ebb and flow problem.

I'm setting up a ebb and flow system but to put the Res. under my tray will cause me to loose to much growth height. How can I get my tray to drain if the Res. is higher than the tray. Also it only takes like 3 min. to flood my small tray.

I guess you could have another pump in the plant tray to pump the water back into the res? - but i think finding a nice flat tray would just be much easier even though you'll loose some hight.

My box is only 46 inches tall, with the height of the Res(13") the tray ht.(6") and a gap of a couple inches between them its about 2 ft. Then my light hood is about 8" so I'm left with only 14 inches to grow in. Plus I wanted to use a screen about 6-8 inches above the tray.
what I want to do is put the Res. outside of the grow room so I can keep the trays lower to the ground. Filling them will be no problem, but draining will be working against gravity. I think it will be to hard to time another pump to drain before it overflowed. Plus I would have to buy 2 one min. Interval timers that are expensive.

Yeah - you're right. Getting late here ;O))

Nobody else has any ideas??
After alot of thinking I've come up with, I could raise my entire grow box off the floor, And with the Res outside the box it would make the tray higher than the Res. But its a big F'in box and heavy as hell.
or because the box is on 3" casters with a shorter Res I can put the tray 2" above the Res and have 13" of space above my screen. My last scrog in this box yeilded 12" colas (in soil) so it will be tight with only 13" but doable with alot of training.
Last I could sog it, but I don't like the idea of so many plants growing at one time in a perpetual sog, its way over my limit.(12).
So ill continue to think about, any input would be most helpful.

Pictures will help allot. I think your screwed Anyway you put it with a 4' box. 18" for hood. 14" for space between the light and plants an then containers that are at least 18" tall. Ummm how was this supposed to work? You could put a timed pump in the table to fill and then a float controlled pump to empty it. Both pumps would run at the same time when the float turned on so the flood pump has to have 3/4 hose while the drain would have 1/2.

Honestly though you have issues with height regardless it seems. The other solution would be build an external Rez out of plywood and plastic sheeting. Just make it long, wide and short. 4' x 5' x 3" will hold 35 gallons.

So a timer would turn on both pumps at the same time, say a 185gph with 1/2 line to fill the tray, and a 264 gph with 3/4 line to drain, controlled by a float valve that opens at like 4" flood ht. ? But the tray wouldn't completely drain because the float would close the drain valve at water levels under 4".
If I use the float valve to turn off the fill line at 4", and use a drain pump that's weaker to drain constantly, wouldn't that work? Mabye start the fill pump a min. before the drain, so it drains an extra min. after the fill stops to completely drain the tray?

I personally thought of lifting your box like you said. You could put a hole on the bottom of the side of your Rez get some gromit that will fit the pump tube so there is no water leak. Then get enough tile to raise your box off the ground a couple inches and let gravity do the rest.

You could also build a stand for your box (kind of an addition to the box that goes underneath and you can use it for Rez storage / seedlings? Hopefully this gives you ideas.

I think that's what I will try. Its Gonna be hard to do by myself(no one else knows I grow). I think if I get a rope pulley attached to the ceiling I could lift it myself and throw some concrete blocks under it. Ill give it a try, easier than messing with pumps, timers, and floats.

If I may ask, why use the box anyway? Doesn't sound very stealthy with the external res anyway.

Stealth isn't the only reason, I have an 8x8 room to work with and have cloning,germing, vegging, and flowering all in the same room. All the boxes are as big as I could make them(had to be constructed in that room) they are all light tight and ventilated perfectly (for soil growing anyway)

I use black plastic to partition my rooms off. Low cost, no light leaks.

Drain To Waste