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Help with 4x8 ebb & flow drainage.

D

Dabbado

New member
So my ebb & flow tables are not draining properly. They are 4x8x5 hydrofarm trays and the medium is 3in rockwool cubes. I have the tray flooding to 1 1/2in. But for some reason not all the water is draining from the bottom channels. Which causes my 55 res to drop a couple of inches.

So what I am asking is what is the best way to achieve complete drain. While still allowing the plants to get about 1 1/2in of water.
 
T

TheCheebaCohiba

New member
How/where do you have your drain fittings placed on the tray? Each end of the tray should have a recessed area with two dimples. that is where you should be putting your fittings with a 1/4 in inlet which is your water in from reservoir then the 1/2 for drain. Set your flood level by using the risers included with your ebb & flow fitting kit. The water in from your pump should have just the little basket net this way when your pump turns off the water drains back down your pump. Remember the rockwool is also going to wick up and hold water. If you were always getting 55 gallons back then your plants aren't taking up water. A small amount of water remaining in the channels is fine. Please post a pic of your setup and I can assist you some more.
 
ThePizzaMan

ThePizzaMan

Active member
Veteran
Hey man..you need to prop one side of your tray up at an angle so that the water drains. I just put a 2x4 or a piece of wood under one side and it should take care of your drainage problems. A flat tray will not drain 100% so you have to angle them slightly.

Peace

TpM
 
toastfighter2

toastfighter2

Active member
Like TPM said, add some pitch to the table so it drains better, but I have also recently realized that using a 3/4" "drain" fitting helps my tables fill AND drain faster
 
Fixer

Fixer

Active member
A sheet of MDF and a couple of tapered 2x4s. If you can get 1" of pitch along the whole 8' you'll be fine.
 
brickweeder

brickweeder

Well-known member
only problem with 1" pitch when flooding to 1.5 inches in a 8-foot long tray is that the raised end will only flood 1/2" and everything except the low end will be less than 1.5". Less pitch would be better.

Options include raising the flood level and less pitch along the 8 feet, or using two 4x4 trays with say 3/8 to 1/2" pitch across the 4 feet, and alternating the floods. between trays. Still will get differential flooding levels within the 4' trays, but with the wicking action of RW, may not be noticeable.
 
Fixer

Fixer

Active member
brickweeder said:
only problem with 1" pitch when flooding to 1.5 inches is that the raised end will only flood 1/2" and everything except the low end will be less than 1.5". Pitch makes more sense for dtw.
Click to expand...


Any amount will help. If you can't pitch it much tip the table across the four foot dimension to drain on one of the long sides. Level your table across the eight foot side. You might get away with ab 1/8 of an inch. You only have to pitch it enough to help the fluid toward the drain. Also a 3/4" drain will help.
 
TahoeTops

TahoeTops

Active member
Why can't they make a tray that actually does drain? We should not have to put shims under one side.


I figure that tray would outsell every other one!
 
Fixer

Fixer

Active member
TahoeTops said:
Why can't they make a tray that actually does drain? We should not have to put shims under one side.


I figure that tray would outsell every other one!
Click to expand...


I think it would make molding the table more expensive and it's not completely necessary for other growing methods. You could always modify the tray by filling the channels with a self leveling material like molding urethane. Tip your tray up to whatever angle you want the bottom at and fill the channels with the leveling compound. Once it cures set the table flat and the channels will be angled.
 
Fixer

Fixer

Active member
Definitely find something that flows well and sticks to plastic. I'd rough up the plastic with sandpaper before application. :)
 
Mr. Stinky

Mr. Stinky

Member
I just drill a small hole between the 2 fittings. my tables are almost level. The pump outruns thelittle hole, fillsthe table to the standpipe, runs a few minutes more, then quits. Water drains back thru the pump till its level with the fitting, then the rest trickles out slowly thru the little extra hole.
 
Last edited:
f-e

f-e

Well-known member
Mentor
Veteran
Mr. Stinky said:
I just drill a small hole between the 2 fittings. my tables are all level. The pump outruns thelittle hole, fillsthe table to the standpipe, runs a few minutes more, then quits. Water drains back thru the pump till its level with the fitting, then the rest trickles out slowly thru the little extra hole.
Click to expand...

I was looking but they sell a few trays. I guess the pump fitting being at the end means it's some distance up the wall. Even if a few MM that's a few MM that won't drain. So you have a drain hole put in yourslf, that's lower than theirs?
 
Mr. Stinky

Mr. Stinky

Member
Yep. Rightin the lowest point. About a 6mm hole. Might have to unplug it every once in a while if you have shaggy rockwool, but itll drain the table dry like you want
 
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