DIY Ebb & Flow - Lucasized - Under $100

DIY Ebb/Flow

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This DIY (formulas, sizing, etc) is based on the ideas and opinions put forth in the Ask Lucas thread and associated posts. This is not the only way to skin the cat, but it is the one being discussed here. If you see another system and/or grow style that appeals to you...find some one doing it successfully and do exactly what they're doing. Do not try and mix and match systems and styles...find something that works, do it. There is no need to reinvent the wheel!

Parts List

This can be accomplished almost entirely at Home Depot:

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Strong Box brand storage tote/bin (27 gallon) $14

- Sterilite and Rubbermaid bins get less stable as they get larger, this one is pretty rigid. The body is black so only the lid will need painting.

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Cement Mixing Tub $6

- The one for this build is 27.5” x 19.5” x 6”. There are larger mixing trays, and the math works for them with the above reservoir. This application requires a more narrow footprint, hence the smaller table. Far superior to a shallow Rubbermaid or Sterilite tub, these mixing trays are completely opaque and heavy duty.

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Active Aqua Submersible Pump - 160gph (AAPW160) $14 at a local hydro shop

- The Depot has some $20 pumps in the pond/fountain area. Do not use smaller than 160gph. The 160gph size is too small if the flood table will sit higher than on the reservoir. Anything bigger than 300gph is too big!

1/2” vinyl tubing (or whatever size you need for your pump/table fittings)

This build uses a piece of a ten foot section probably purchased ten years ago. It's cheap, no more than 14” will be necessary if the flood table sits on the reservoir. If the table will be apart from the rez, tubing for a return line, 3/4”, will be needed. Purchase table fittings and pump first to ensure appropriate sizing. If table is apart from rez and water lines are exposed to light, they should be opaque.

1 ¼” hole saw $15

- A paddle bit may suffice, but biting the bullet and starting to buy quality tools as needed for grow projects is recommended—it doesn't have to be the most expensive, but get better quality and take care of them! If this ebb/flow table is the first, it won't be the last thing the do-it-yourselfer will build, and decent tools will make ALL the difference in much of what is done in the future. People who have gnarly sets of tools gathered them one at a time! :-)

Digital timer - $15

- A digital timer can be set for less than 15 minutes. It will likely take just under five minutes for the table to flood, an analog timer may be used, but with the extended underwater time, the use of the air pump becomes less optional.

2 – 4 watt air pump (optional)

- Based on light size, the recommended air pump is as follows: watts/100 = air pump wattage. 400/100 = 4 watts. This formula is most appropriate for DWC. Ebb/Flow is far more forgiving where dissolved O2 is concerned, a smaller pump is acceptable. Four inch stone.

Hydro store or online:

Hydroton clay pellets - ~$20

- The Depot online actually has a 50 lt bag of a hydroponic stone for $30, can't say I've ever seen it at my local store.

Botanicare Ebb & Flow Fittings Kit - $7

- The 1 ¼” hole saw is needed to install this properly

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Squat/short containers (price varies for your application)

- This application uses one quart pots(about 4 ½”) purchased at Home Depot with plants in them! This unit will be used for a fairly short veg immediately following cloning in a bubble cloner. 6-12 small plants will veg at a time, they'll be transplanted to larger pots when they go to the flower table...a perpetual SOG of sorts. This table can be used to finish 4-6 moderately sized clones (shorter veg, well pruned)...a larger diameter potting container can work, but more than six or seven inches tall is too tall. The max level of hydroton will be 5-6”.

continued...

Edited by CasualObserver, 16 May 2012 - 06:44 PM.
cleaning up

That's awesome dude. For a while I considered going ebb & flow. If I do, I'll be using this guide to make my set up.

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This application's foot print must be as narrow as possible, so the table is oriented parallel to the reservoir. That black circle is the lid to a small Folgers can. It will serve as a cover for a small access hole.

If the grow space allows the table to sit perpendicular to the rez, this would be more stable. Or if the gardener is using the larger mixing tray, it wouldn't matter which way it sits, it would be wide enough either direction. As this tray is not wide enough to sit securely on the rez, 1 ¼” dowl rods are used to stabilize. (see image in last post of DIY - Figure 032)

Think about how the table will be used (how many plants and their configuration in the table). This application will be using as many as 12 one quart containers, so it is necessary to be mindful of the location of the fittings. If the unit will be using two, four or six larger containers, fitting placement is not that important, but it helps to pay attention...once the holes are drilled, they're drilled. Generally speaking, toward the middle works well.

Regardless of where the fittings are installed, a small amount of water will remain in the table after a flood (This is not desirable!). A small hole, or two, will be necessary to completely drain the table. The placement of the small drain hole should be in the lowest part of the tub (waiting for final installation where the unit will be used may be wise). The intention here was to thread the fittings through both tray and lid, securing with the provided nut, which would pull the center of the tray down slightly, but there is too much space between the lid and tray...it just so happens one of the lowest places in the tray is in the center.


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The Strong Box lid has small notches in the center at either end of the lid (pointing), they work nicely as a starting point for fill/drain holes. The mixing tray (flood table) center is also pretty plainly marked...another great landmark for measuring and drilling holes. The only caution with these holes is ensuring they are completely within the raised squares or in the trough. The larger hole in the lid that allows water from the small hole to pass easily should be in the trough...should there be any leaks or arrant water, it will follow the trough back to the reservoir (in theory, anyway).

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Edited by CasualObserver, 16 May 2012 - 06:26 PM.
cleaning up

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It seems obvious, but probably worth mentioning to be mindful of what is behind the item being drilled or cut. (Disregard the attack poodle turning her face from the camera for privacy reasons ).




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Using the 1 ¼” hole saw, drill holes in the table and rez lid for the ebb/flow fittings. Lining up the holes in the table with the holes in the lid may be a little tricky...in this application, the fittings were best placed 6” apart, 3” from the center of the tub. The 1 ¼” holes in the tray will be VERY snug for the fittings. So in the spirit of keeping the DIY replicable, instead of using a tap and die to thread the holes, a threaded 1” metal pipe was used to screw into the holes...it helped, but getting the fittings installed in the tray took a little force. Ensure the rubber washer is inside the tray/table.

Edited by CasualObserver, 16 May 2012 - 06:30 PM.
cleaning up

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By providing an access hole for testing and topping, and using the Lucas formula and addback plan, the gardener doesn't need to dump and change the reservoir during a grow. If a feeding schedule that requires dumping the rez is preferable, it's recommended that a pump be utilized for draining, or, place the table above and away from the reservoir. Moving the table when it's full of plants would be less than fun, so think ahead! The access hole--size and what it's covered by--may be whatever is preferred by the gardener. The type of hole cutter shown makes a very sloppy cut in plastic.

The Strong Box tote is 27 gallons, but that won't be the working volume used in the grow. Measure a known volume of water, mark the level in the reservoir. Installing a sight glass using a couple grommets, elbows (available at a hydro store) and a piece of clear vinyl tubing is an option...handy, but not necessary.

For this application, 20 gallons will be used. To find the needed volume of water, multiply the dimensions of the water table W x L x H (height of water level ~4”). By example: This flood tray is 27.5 x 19.5 x 4 = 2145 cubic inches. Multiply the tray volume by .0043 to convert to gallons: 2145 x .0043 = ~9.25 gallons. An adequate amount of water must be left in the rez during the flood cycle to ensure the pump remains submerged, so the grower must take this into account when deciding how much water to actually use. The math above isn't completely accurate due to the shape of this particular tray, but it's skewed in a conservative direction, so all is well. The more water in use, the more stable the soup will be over the long run...it's better to have more than the minimum needed.

A proven formula for sizing a reservoir based on light size is watts/25. For this application a 400w CMH will be used. 400/25 = 16. Using 20 gallons meets the minimum requirement. For a 600w lamp (600/25 = 24 gallons)...this reservoir is capable of supporting a 600w light.


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Paint reservoir lid to make it completely opaque. The hole in the lid meant as a pass through for the small drain hole should be left open; install water pump and optional air pump. Hose clamps may be used, but if the fittings are somewhat snug, shouldn't be necessary. Test it, if there's a question or concern, clamp it.

Edited by CasualObserver, 16 May 2012 - 08:03 PM.
clean up

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Add containers, hydroton and water...test.

Disassemble and clean everything before use.

See AskLucas.com, The Ask Lucas Knowledge Base | The Lucas Formula | Hydroponic Gardening, for information concerning nutrients, container size, flood cycle timing and a wealth of other tips and suggestions regarding your foray into hydroponic gardening! It's a collection of Lucas posts from the Ask Lucas thread.

Happy Growing!

Figure 032
1.25" dowl rods to support narrow table on reservoir
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Edited by CasualObserver, 16 May 2012 - 06:37 PM.
clean up

That's awesome dude. For a while I considered going ebb & flow. If I do, I'll be using this guide to make my set up.

Thanks Makizushi! I've got another idea for using a pre-made table (bigger than this one, for sure), and a commercial trash can...stay tuned!

For a second there I thought you were going to put the Cement Mixing Tub in the tote an then cut holes in the totes cover and put the net baskets in there... I like that Idea! I like your Idea too... But would this tub fit in your tote with the cover over it and still be sturdy? I'm only asking because I'm looking to save as much height as possible in my small room.

SC, I always intended to use this for rooted clones to get them established and ready for the big table (flower room). The unit was measured for the propagation chamber, but not so much for the shelf it was intended to sit on...I wound up dropping the flood tray (cement mixer) down into the res tub and didn't use the lid at all (sacrificing a little usable res volume).

You could certainly modify this to use a couple tubs that fit together (shallow tub as the flood tray, nestled into the larger res tub), and use a tub lid as you are suggesting. You'd simply need to ensure the max flood level is high enough to adequately soak the suspended netpots...probably easily accomplished by using 6" netpots and the most shallow upper tray you can find. You'll also need to have a large enough res that when the flood tray is full, your pump doesn't run dry!

Play with it and post your experiences!