Building a DIY Hydroponics System Part 3: The Reservoir

Building a DIY Hydroponics System Part 3: The Reservoir

This is Part 3 of a 7 Part Series of how to build and manage a DIY Hydroponic Lettuce System!

Other Articles in this Series:
Part 1: The Rail System
Part 2: The Support Structure
Part 4: Lighting
Part 5: Nutrients
Part 6: Planting
Part 7: Harvesting

Note about links: We have linked to certain products that we have found useful when building our hydroponic systems. Some of these links may be affiliate links and as an Amazon Associate we earn from qualifying purchases after clicking one of these. We take great care to only link to products we have found to be useful - products we would recommend to a friend or family member building this system - but you are more than welcome to use other products instead.

The water reservoir is where all the excess nutrient water is stored as it's being pumped through the hydroponics system. Here's what you'll need to get started:

Supplies:

  • (1) Heavy-duty, dark colored opaque tote with lid - 15-25 gallon
  • (1) 1" ID Pond Tubing - Cut to desired length (Amazon)
  • (1) 1/2" ID Pond Tubing - Cut to desired length (Amazon)
  • (1) Submersible water pump (sizing info in Step 5) (Amazon)
  • (1) Air pump with air stones (Amazon)
  • (1) Aquarium heater (optional, see Step 7)
  • (1) Cable Tie (optional)

Tools:

  • Cordless Drill
  • Hole Saw Arbor (Amazon)
  • 1.25" Hole Saw (Amazon - this fits the same 1/2" arbor)
  • Safety glasses
Step 1: Drill Holes

Position the reservoir in its desired location beneath the inflow/outflow end of the rail system. Using a hole saw, drill two 1.25" holes in the lid of the tote to allow inflow and outflow tubing to enter the reservoir. The location of the holes is up to you, as long as the tubing is fairly straight and has no loops where water could collect. Note: Your holes will not match up exactly with the holes in the picture above - ours has two different systems pulling water from it.

Step 2: Cut Tubing

Cut the 1" tubing and 1/2" tubing to be long enough to travel from the bottom of the reservoir to the inflow and outflow elbows on the rails.

Step 3: Insert Tubing

Insert the tubing into the holes in the reservoir lid. The 1" tubing should fit fairly snug, while the 1/2" tubing will have extra space - this extra space can be used to allow the power cord for the pump and airlines to enter the reservoir.

Step 4: Connect Tubing to Rails

Press 1" tubing onto the outflow elbow and press 1/2" tubing onto the inflow elbow. Twisting back and forth will help you make progress.

Connect the tubes

Step 5: Install the Water Pump

Place the submersible water pump directly in the reservoir and pass the power cord up through the inflow tubing hole (you can also drill a separate hole if needed). Attach the end of the inflow tubing to the pump. The pump should include an adapter that fits nicely inside the 1/2" tubing. You can use a cable tie to further secure the inflow tubing to the pump so it doesn't wiggle off as time goes on. The sizing of the water pump is dependent on the height of the rails above the reservoir:

(Note: The product listings for these pumps changes often so make sure the link takes you to the right size pump)

Rail Height Above Reservoir Pump Size
<2' 130 GPH
2' - 3.5' 320 GPH
3.5' - 5' 550 GPH
5' - 6' 660 GPH

Using a pump that is too small may result in the pump being unable to lift the water up to the rails and using a pump that is too large may result in the rails overflowing as they cannot drain off the water fast enough. These pumps from KEDSUM (links in table above) have been very dependable - we've run them constantly for over a year without any issues.

Step 6: Install the Air Pump

An air pump is used to keep the water oxygenated which promotes root health and growth. The air pump is placed outside of the reservoir with airlines routed into the reservoir with air stones attached to the end. The tubing can be routed through the extra space in the inflow tubing hole or through a separate drilled hole. The air pump can be put on a towel or piece of foam to reduce vibration noise.

Step 7: Install the Water Heater (for cold locations only)

If the reservoir is stored in a cold location, an aquarium heater can be used to keep the water temp near 70 degrees. In our experience this allows the lettuce to grow faster but is not needed, especially if the reservoir is in a warm location. We have our reservoir on the floor of a four-season porch and we noticed the water temperature could drop into the 50s during cold winter days. A simple aquarium heater such as this one can be set to a desired temperature and then left alone.

Your reservoir is ready to go! Onto the lighting, which is Part 4.