Testing the Ebb and Flow Hydroponic Table

The ebb and Flow hydroponic system test didn't go great, today. There was an enormous amount of thought and preparation that went into the construction and design of the recycled hydroponic system. The parts were all purchased, math and physics seemed to work, and in theory when all plumbed, we'd be ready to introduce nutrient solution and plants.

Here's where I started the day...

I had determined that the 100 gallon reservoir selling for over $250 dollars was too expensive. I considered stacking a couple and installing a float valve to keep the nutrient solution level correct. The problem was that the stackables that were affordable would be too tall (stacked) and would not fit under the ebb and flow table. The solution was to daisy chain three reservoirs together, it would be the only way to hold enough nutrient solution to flood both halves of the table (See the plan my The New Ebb and Flow Hydroponic Table blog).

I purchased three 3/4 inch threaded fittings for the reservoirs, a couple of in-line valves, some 3/4 inch tubing and few items I'll need later. The fittings installed easily and lifted the table to place the barrels underneath (it was a snug fit). I was pleased with how they looked and the ease of the project to this point.

One of the fittings for a shutoff valve was actually a 1/2 inch and not a 3/4 inch, so I needed to make some quick amendments since I was anxious to test the ebb and flow of the system.

I had installed valve in the "T" from the pump to be able to run each side of the system independently.

I connected one of the reservoirs to the main reservoir that held the 530 GPM pump and shut down one of the valves. It looked fantastic and was ready to go.

I introduced water to the system through the table. I wanted to see how well it would drain back through the pump. It worked relatively well, although I noticed that the pump fitting was not completely flush to the table and would likely leave 1/4 of an inch of nutrient solution in the ebb and flow table (This will require some work later), and there was leaking around the fitting. I'd need to find a product or additional gaskets to stop the leak.

Although I had done the math to calculate the amount of nutrient solution I'd need to fill the table to a depth of 4.5 inches (67 gallons) and anticipated needing an extra 10-12 gallons to keep the pump from running dry (at least when the system was empty), I wasn't sure of the depth in the reservoirs this would require.

I had been anxious to turn on the pump and did so when my reservoir became 1/2 full. The pump was fantastic, the quick flow to fill the table was exactly what I was looking for. I realized that the amount of nutrient solution it would take to fill the table to 4.5 inches was going to overflow my center reservoir (the small storage bin one), so I aborted the fill up. Draining went fine, except for the leaks that continued from a couple of the fittings (small).

I emptied the system by draining onto the greenhouse floor (luckily it drains well).

Lessons learned, items to consider and adjustments to make, in the next round.

1. Fix the seals at each fitting including the pump fitting on the table.
2. Put the third reservoir on-line and test the one side operation.
3. Replace the small center reservoir with either another 55 gallon trash barrel or the largest storage tub I can find. If I go with the storage tub, I may want to build a wooden frame around it for additional support/strength.
4. I'm still seeking a solution to the 1/4 inch of nutrient solution that may sit in the top. I'll either find a way to make the fitting flush or may add some aeration stones and add a small platform to rise the bottom of the plants out of the solution (very aereoponic-like).
5. I need a plan for draining the system, like a "T" with a valve that can drain the system out of the greenhouse.