NOTE: Dec 2021 – pictures for this blog post are gone. Unfortunately I had hotlinked the images to a Google document that the author shared with me which is no longer up. I’ve made a few attempts to contact Tollas to get the images without success. I’m going to leave the part list and blog post up but unfortunately it’s not gonna be nearly as useful without the photos. Sorry about this. Try contacting Reddit user Tollas and he might be able to help you out.

This DIY post is on building a waterfall re-circulating DWC (rDWC) system. Advantages of rDWC include: only having to check one tank, no root competition like in 2 plant DWC systems (the jury is out on if this has any advantages), and the ability to use water chillers. This is an advanced setup and I would recommend starting with a regular DWC reservoir if this is your first time in hydroponics.

Credit to reddit user Tollas for putting this excellent write up together. You can find him on Instagram or on Grow Diaries. And of course to PA hydroponics who put together the video that this post is based on.

Overview

I wanted to build a fairly simple Waterfall RDWC setup. The system needed to support the following:

• Inexpensive: Keep the total build cost under $1K USD.
• Modular: Must be able to easily remove and replace parts due to wear or damage
• Design: Should be able to adjust the base design for different numbers of plants, grow area, and varying part dimensions.
• Simple: Anyone with basic knowledge of tools should be able to build this.
• Use and Accessibility: Must have an external reservoir and an easy way to drain/fill the system that doesn’t involve moving plants.
• Safe: All parts must be hydro or food safe plastic.

Risks/Assumptions

I recommend measuring your actual build space and components for tube lengths after you have your tent, buckets, and bulkhead fittings. You may need to adjust some to accommodate your space and materials.

Tools

• Electric drill
  • Hole saws:
  • 3.5”/89 mm
  • 1.25”/32 mm
  • .75”/19 mm (or step drill bit)
  • Drill Bit Set (1/4″ & 3/8″ required)
• Deburring Tool*
• Tube Cutter*
• Silver Sharpie
• Tape Measure

* This can be done with a razor knife, but it’s much more difficult. Worth the tool cost IMO.

Parts List

General

Water – Inflow

Water – Return Flow

Air

Containers

Other/Misc

• Copper mesh – Cover bulkheads inside of plant buckets
• Silicone adhesive – Seal leaks on outside of buckets as needed
  • Use aquarium safe silicone
• 2×4 lumber bits to raise buckets as needed

Basic Diagrams

½” Inflow

1” Return Flow

Buckets

Cutting Holes

When cutting holes for the bulkheads, cut them as close to the bottom of the bucket as possible, but be sure to leave room for the bulkhead to fit and account for the bottom of the bucket width. If using the 4 gallon square buckets and bulkheads I used, measurements will be listed. Otherwise you will need to adjust. Be sure you’re using square buckets. Round buckets do not have a good surface for attaching this style of bulkhead.

Things to note before cutting holes:

• Be careful of slipping prior to drilling your pilot hole.
• Run the bit forward until you start to bite, then reverse it. This will make the holes cleaner and cut rather than potentially melt or tear the plastic.
• When cleaning the holes with the deburring tool, test fit parts continuously until it fits snugly or with very little resistance. Cutting too much will create leaks or loose joints.
• After cutting and deburring, wipe down the buckets with a dryer sheet to remove all the little bits that cling to the bucket.

1x Reservoir Bucket:

• Cut 1x 1.25” hole on the front, centered and 12” from the top
• Cut 1x 1/4” hole on the front near the top for the water level kit clip
• Cut 1x 1.25” hole on the back, centered and 12” from the top
• Cut 2x 1.25” hole on the back, each 2” from center and 12” from the top

6x Plant Buckets:

• Cut 2x 1.25” hole, one on each side, centered and 12” from the top
• Cut 1x 3/4” hole in the front close to the top
• Cut 1x 3/8” hole in the front about 1” below the 3/4” hole

6x Lids

• Cut 1x 3.5” hole in the center

Assembling

Note: When attaching bulkheads, be careful not to overtighten. This can cause the gasket to warp or be shoved out of place and can cause leaks. They should be hand tight only.

Reservoir Bucket:

• Attach the water level kit bulkhead fitting to the front.
• Attach the 1/2” bulkhead fitting to the center of the back.
• Attach two 1” bulkhead fittings to the remaining holes.
• Tighten all fittings, test for leaks, seal with silicone as needed.

Plant Buckets:

• Wrap the interior portion of the bulkhead fittings with copper mesh
  • This prevents the plant roots from entering the return flow system
• Attach one 1” bulkhead fitting on each side. Be sure the copper mesh is fitted securely between the fitting and the washer
• Tighten all fittings, test for leaks, seal with silicone as needed
• Place the net pot in the lid and secure with silicone as needed

Tube:

• When cutting your tube, label the length of the piece. It will make things easier during assembly.
• For any tube that is curled, submerge the tube in nearly boiling water for a few seconds .and then straighten it and hold it straight until it cools and holds its shape. CAUTION! It will be hot!

• Attach all 1” tube and fittings as shown in the above diagrams.
• Attach all 1/2” tube and fittings EXCEPT for the plugs which go inside the bucket.

Testing

• Start by pouring enough water into the plant buckets to completely cover the bulkheads. This will take ~10 gallons.
• As you are filling the system, check for leaks around the bulkheads. Also check for return flow back to the reservoir.
• Next, turn on the water pump and check for flow rate into the plant buckets
  • Note: Based on the flow rate of the pump, this will determine if the 1/2” plugs are needed and what size of hole to drill in the end
• If the flow rate between all buckets is not the same or close, drill out a small hole (I recommend starting at 1/4” and working up) in the 1/2” plugs and insert from inside the bucket, then re-test the flow. If too powerful or it is causing leaks from back-pressure increase the hole size and test again. The goal is to have all buckets relatively similar, but not a jet of water and no back-pressure on the pump. Once satisfied, fully set the plugs and drain the system.

Finishing Up

• Soak the air stones in 3% hydrogen peroxide overnight
• Run the air pump lines into the 3/8” holes on the front and attach the air stones. Run air the pump until the stones are dry.
• Perform a final leak test. Re-tighten and apply silicone as needed.
• Completely drain the system and fill 4-5 gal at a time. After filling and covering the bulkheads completely run the system for 30 min and let it equalize. Mark the level on the water level indicator using the silver Sharpie and note the total gallons. Add additional buckets of water and re-mark after the system equalizes each time until you reach your desired maximum water level.

Congratulations! You now have a waterfall RDWC setup! Enjoy!

Appendix

Item Reference Images

Item	Image
Bulkhead fitting
Tee fitting
Elbow fitting
Cross fitting
Plug fitting
Barbed fitting to garden hose
Garden hose ball valve with quick connector
Water level kit  I buy the one from PA Hydroponics, but you can assemble your own from:½” bulkhead fitting½” elbow fitting2 pieces of ½” blue tube (2” and 12” lengths)Optional tube clip or a bit of wire to secure the top

Bucket Cutting and Assembly

Reservoir Bucket

Front

Back

Plant Bucket

Front

Sides

Lid

Other/Misc

Use & Maintenance

• To drain the waterfall rDWC system, I recommend an inline pump.
  • Turn off the water pump
  • Attach the pump to the garden hose ball valve and drain as much as possible
  • Drain the remaining water directly from the reservoir
• When filling, be sure you do not overfill. The water should be below the hole for the air line
• For plant training, use binder clips or command strip hooks
• If your plant buckets are not properly draining, check for root blockages near your bulkheads. You may need to wrap with additional copper to prevent this
• After a grow, check the copper wrapping on the bulkheads and replace as necessary after cleaning & disinfecting the system