Richard bray

Step 20.
Use the 1" male threaded to slip adapter to trace a hole in the back right corner of the grow bed. Cut out the hole with a box cutter.
Step 21.
Make the bell siphon:

• Cut lines or drill holes into the 14" length of 4" PVC pipe to make the media guard (See illustration).
• Place a 4” cap on top of the media guard.

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• Attach the 3/4" to 1 1/2" bell adapter to the 6” length of 1” PVC pipe.
• Attach the male threaded to slip adapter to the bottom of the 6” length of 1” PVC pipe.

Bell adapter
Male threaded To slip adapter

• Place an o-ring over the threads of the male adapter, and slip the threads through the hole in the back right corner of the grow bed.

Bottom of grow bed

• Place another o-ring over the threads of the male adapter, and then screw on the 1” female threaded to slip adapter. This completes the siphon.

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• Cut 1/2" notches into the bottom of the 7 1/4" length of 2 1/2" PVC pipe (See illustration].

Notches
PVC Pipe

• Put the 2 1/2" PVC cap on the top of the 7 1/4" length of 2 1/2" PVC pipe. This is the bell.

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• Place the bell over the siphon.
• Place the media guard over the bell.
• Attach a 1” 90° elbow to the bottom of the female threaded to slip adapter.
• Attach a 6” length of 1” PVC to the 90° elbow.
• Attach another 1” 90° elbow to the end of the 6" length of 1" PVC pipe.

Step 22.
Rinse off the grow media thoroughly. Place the grow bed tote into the grow bed cage. Fill the grow bed with media, leaving at least 1" of space between the media and the edge of the grow bed.
Step 23.
Add an air stone into the fish tank.
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Step 24.
Turn on the water pump. Check to make sure water flows up into the grow bed, and that the bell siphon drains it back into the fish tank. Check for leaks around the IBC valves and the bell siphon fittings. Use 100% silicone to seal any leaks in the tote, and use dope tape to fix leaks in the PVC pipe. Use valves to adjust water flow into the grow bed if the bell siphon is not draining properly.
Step 25.
Once the water is circulating appropriately, cycle your system.
Each of these systems omits the need for a sump tank because the grow bed sits directly on top of the fish tank. This reduces the amount of space the system will use, and it also reduces the amount of plumbing to build and clean.
You can scale any system up or down as long as you keep a 1:1 ratio of fish tank volume to grow bed volume. However, while these designs can be scaled up, DWC systems are best for large operations.
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Alex Francis Pro/Shutterstock.com
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