| To Retrofit Existing Benches | A New EBB-FLO System | What About Tanks |
How Big Should Tanks Be |
What About Pumps |
Controls, Valves, Etc. |
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NEEDED TO RETROFIT EXISTING BENCHES:
1. The EBB-FLOW polystyrene inserts.
2. A sturdy bench support system.
3. Some means of leveling the bench/inserts.
4. Pump(s) sized for the installation.
5. Tank(s) to hold the recirculating water.
6. Common PVC pipe and fittings.
7. One or more HS or Quick valves to connect to each bench.
8. A controller if you wish to automate the watering and feeding.
Back To Top Of Page Picture Of EBB-FLO System With Retrofit Bar
NEEDED FOR A NEW EBB-FLOW COMPLETE BENCH SYSTEM:
Complete EBB-FLOW benches from Midwest GROmaster, Inc. include:
Galvanized steel (Allied Tube) legs, leveling headers, and bench framework.
Extruded aluminum side and end rails.
Polystyrene tray inserts.
All parts are pre cut, and pre drilled, ready to assemble, with all necessary glue and fasteners.In addition for a complete system, you will need:
1. Pumps sized for the installation.
2. Tank(s) to hold the recirculated water.
3. Common PVC pipe and fittings.
4. One or more HS or Quick Valves to connect to each bench.
5 A controller if you wish to automate the watering and feeding.
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Most customers purchase their tank(s) locally. There are several possibilities. The most common is to use the large round white poly tanks available very reasonably from the local farm supply store. The tank(s) are usually placed at ground level at one end of the greenhouse, or better yet, in a nearby non-growing area. The gravity drain from the benches is directed to one or more sump pits in the greenhouse area, and a high capacity sump pump returns the irrigation water to the main storage tank. Another system used by some growers, especially in new construction, is to bury a 1200+ gallon septic tank at one end of the greenhouse. The gravity drain from the benches can go directly into the storage tank, eliminating the need for the sump pump. However, cleaning or maintenance of this type of tank can be more difficult, since it is under ground. We would be happy to make recommendations/suggestions for tank(s) for your specific situation.
Back To Top Of Page Picture Of Typical Tanks
As a rule of thumb, it takes about 1/2 gallon to flood one square foot of EBB-FLOW bench. First you must decide how many square feet of bench(es) you wish to flood at one time (one "zone"). Divide this number by two. This is the number of gallons required to flood one zone. If you are going to flood one zone right after the other, your tank will need to hold a minimum of three zones worth of water, as the water draining back from the first zone will not be back in the holding tank until the third zone is watering. NOTE: Controllers from Midwest GROmaster, specifically designed for use with sub-irrigation systems, have a "pause" feature that allows you to program a pause between the watering of each zone, to allow the system to recover the returning water from one zone before watering the next. Also, if you are filling the tank manually, you must consider how often you wish to fill the tank. As a rule of thumb, the plants will take up about 8% to 10% of the water each time the bench is flooded.
With the large computerized controller/injectors such as the GROmaster 200, and the GROmaster 1000, etc. the water is taken from the storage tank if available, and if not, new water is taken in, always adjusted to the exact EC and PH recipe desired. With this system, the storage tank(s) can be relatively small, as it only has to hold the return water from the last two or three zones that are watered. We have several growers who run an acre or more of EBB-FLOW benches with one or two tanks that hold 1000 to 1200 gallons with a system like this.
Picture Of Typical Tanks Back To Top Of Page
Our engineering department can make recommendations for the sizes of pumps needed for your specific project. We recommend purchasing high quality stainless steel pumps. The pumps that we sell are high quality American made stainless steel pumps. For example our 1/2 HP sump pump is all stainless steel and rated at over 60 GPM. It is important to make sure that your sump pump(s) have sufficient capacity to keep up with the water draining back from two or three bench zones at one time!
Information On Pumps Back To Top Of Page
WHAT ABOUT CONTROLS, VALVES, ETC.
To fully automate the watering of a system of EBB-FLOW benches, you will need a controller (or in some cases an addition to an existing system such as your environmental controller) that can:
1. Turn on the main system pump when watering is called for.
2. Open the solenoid valve for the zone where watering is called for.
3. Time each zone as needed to fill the benches to the desired level.The EBB-FLOW controllers that we sell, as well as our fertilizer injector/controllers all have 24 volt output(s) for the pump start relay for the system pump, and the solenoid valves that control the water flow to individual zones. Our solenoid valves have flow control, and manual override allowing the valve to be opened manually even if the electric coil fails. All of our controllers have built in clocks that allow for automatic starting of the watering cycle one or more times per day. They may also be started (or stopped) manually, or by an external input. They all also have the ability to "pause" between zones to allow the system to recover the treated water from one zone before proceeding to the next zone.
On small installation, a single bench can be watered from a tank placed below it with a small utility pump (without a check valve) hooked up to the bench with a piece of hose and the HS valve. The pump can be turned on and off manually, or with a simple spring wound timer such as those used with whirlpools and spas. The water is pumped up to the bench, and as soon as the pump turns off, the water drains back to the tank through the same hose.
In larger (multi zone) installations, if you use the HS valve, you must also use a "return" valve for each zone. This is a spring loaded plunger inside a T shaped fitting that allows the water to go out to the bench(es) in a zone, and then return through the same pipe, when the zone valve turns off.
In most larger installations the "Quick Valve is now used instead of the older HS valve. The quick valve costs a little more than the HS valve, and you must run a fill and drain line to each bench. However, with the quick valve, you do not use the return valve (which usually more than makes up for the higher cost of the quick valve), and it has no moving parts. Also, the drain time on the benches is much faster than with the HS/return valve combination.
Information On Controllers Back To Top Of Page