When Death Comes: Weathering the Challenges of Creating New Aquaponic Heating Solutions

When Death Comes: Weathering the Challenges of Creating New Aquaponic Heating

On November 2012, we traveled down to Silverton, OR to pick up 90 tilapia babies. While we were working on building out the greenhouse, we started our first prototype aquaponic system in our basement. It was the perfect environment for us to experiment with aquaponics because we could control the temperature and lighting. When we completed the greenhouse system, we clearly remembered the day that we were able to move them out from the basement into their new homes. We were so excited as they had more space to swim. We could immediately see a difference in their behavior.  They were full of energy and seemed a lot happier. It was a perfect spring beginning.

As we moved into summer, each of us expressed concern about the water getting too warm for them. We had managed to come up with all sorts of ways to address the issue, but to our surprise, we never had to act. As winter moved closer, we began to recognize that we not exactly prepared to deal with heating the water for the fish. Ideally, tilapia like to be in temperatures that are at 72 degrees to 90 degrees Fahrenheit. Here in the Pacific NW, our temperatures can drop below zero, but given that our location is closer to the ocean, it is rare that it stays that way for long. Hour and hours of research left us without much of a solid direction of what to do. When winter did hit, we equipped our one fish tank with two aquarium heaters we designed our selves. Every day, we made sure to carefully check to make sure that everything was working properly.  However, failures do happen.

On November 8th we experienced our first major failure that resulted in massive fish loss.  Nothing could have prepared us for what we saw that morning when we woke up to find a toxic soup of floating dead fish.  The brown, murky water revealed that they had suffocated due to a lack of fresh water flowing into their tank.  Fish naturally emit ammonia as a by-product.  Over time, the ammonia can build up to a toxic level which can cause nitrate poisoning if it is not addressed. This is exactly what happened.

We immediately looked for what had happened.  The cause of the failure was that our sumps (holding tanks of fresh water) had run dry.

The initial shock then shifted into anger and a deep sadness.  The tragedy happened the day before we launched the Adopt A Growbed Program where the public would be participating in learning how to grow aquaponically.

“I didn’t want to do the Adopt A Growbed Program after what happened,” shared Aaron.  “It hurt my heart to see what had happened.  All I could think about is how they depended on us and we failed.  The last thing I wanted to do was face the public and try to share how great aquaponics is when you have to deal with this dark reality.”

We made an agreement to not share what had happened with others until we could process it.

“It was heartbreaking to go through all the way around.  Aaron and Tyler worked to clean out the oily tank and put everything back in order so we could launch the program.  There was a deep sadness in us all and we could especially feel it in the greenhouse.  Over the days that followed, we recognized just how deeply connected we were to our fish and our plants.  I realized that through this tragedy, we were experiencing what most people would never here America – a real connection to our food.”

With a little less than half of our fish gone, we began to devote our attention to solving problems and preventing issues.  In addition to the sumps running dry (which has continued to be an issue), we also began to focus on addressing our heating issues.

The Water ValveFeature ImageThe valves feature a magnet which operates a diaphragm type valve. As the water level rises, a float will rise until the magnet moves a plunger closing the valve.

The solution for the sumps running dry can easily be solved by installing a water valve.  It works by sensing when water needs to be added to the sump tank and then shuts off the water when it is filled.  This completely eliminates the need for people needing to remember to check to add water.

The solution for developing a heating solution is more complicated.  As of now, we are using a temporary solution to heat the water.  We have installed a traditional 55 gallon hot water heater into the system.  We made modifications to the thermostat to regulate the temperature range and ensure the water didn’t get too hot or too cold.  It is not permanent solution because the in and out are 3/4″ and it holds fish solids making it very difficult to clean.

“There really are not any good standard electrical heating solutions for larger aquaponic systems out there,” stated Aaron. Talking with others in our network and Murray Hallam, we just are not seeing any viable products that people can get access to.  This is what caused me to dig in and turn to other industries to see if there might be a solution that would work.”

The Spa and hot tub industry use electric heaters and there are some aquaponics enthusiasts that use the tub as a fish tank.  Their large insulated shells make a perfect container to keep the water warm.  After looking at various spa heating elements and solutions, we decided to try and make our own.  After setting up a wholesaler relationship with a company, we ordered two heating elements to try along with a temperature controller.

“We knew there was a way to get things to work,” recalled Tyler.  “After Aaron and I installed the [two, 4,000 watt] heaters, we didn’t see a difference in temperature change.  The water was simply moving too fast for it to warm it.  We later figured out you had to use a valve to slow down the water flow so you could give it enough time to heat up.”

It was an eureka moment.  Everyone started to feel hopeful again in knowing that we had solved a problem.  However, it was short lived, as we quickly ran into the same issues that had not been addressed.  A little more than a week since the fish had died, the same thing happened where the sump ran dry.  Because no temperature controller had been put on the new heating elements, the PVC melted and the brand new elements were destroyed.

“Once again, we just felt defeated.  Working on such little time and resources to try to keep up with everything that is happening we were just crushed to see the fish suffering,” stated Aaron.

That morning when the problem was discovered, the fish tank chemistry had an extreme level of ammonia build up that was causing nitrate poisoning for the fish.  Slowly, one by one, they began to die off over the next few days.  Once the survivors stabilized, we are left with 50 out of the initial 190.

“I felt completely helpless,” stated Kate.  “To watch everyone work so hard and not have the right tools and resources to remedy the issue was so frustrating for me.  Even know this is part of what we do here at Ingenuity, it was extremely difficult to take your own medicine that you give to others.  We learn so much from our failures and this is why we do this so we can help others not make the same mistakes we do.”

As of to date have attempted to designed water heating solutions for our system and they all have failed.  They are as follow:

  • FAILED SOLUTION #1: We developed a 55 gallon barrel heating system that included an electrical hot water element.  We learned that the barrel was not a good solution because it would build up pressure which would cause it to leak.
  • FAILED SOLUTION #2: We built a 6″ x 2″ PVC with two electrical elements.  It worked for a while, but then eventually melted the PVC because it lacked proper temperature controls.
  • FAILED SOLUTION #3: We built a heater that leveraged some new components borrowed from the spa industry to heat water.  It eventually failed because we did not have the proper controls to regulate it.

So What is the Heating Solution?

We are still looking to leverage the spa heating technology.  After all, it did work, we just didn’t have the temperature controller in place to shut it off so it would not melt the PVC.  What we have found are some really nice solutions that have lots of sensors that can help prevent failures from happening.  We plan on implementing a spa controller to help regulate the heating elements. VS500 Retrofit KitFeature ImageA kit designed to fit any Spa or in our case, Aquaponics system.It is a field proven control system that provides additional reliability and ease of installation. The software-based control system makes decisions based on temperature and flow conditions within the heater.  The system operates properly if there is a minimum of 20 gallons per minute flowing through the heater under all hydraulic variables and at worst case conditions.  The goal for the spa designer ,or in our case the Aquaponics heater, is to design a circulation system that, when used with the proper pump, will provide a uniform flow in either direction through the heater.

In aquaponics we have a few more variables to consider than in the spa industry. For example, we need to consider that we have solids in our systems.   Is it ok to have solids go by the  heating elements?  The answer is yes. However, this is another place to maintain and inspect to ensure solids don’t get built up.  The Spa controller unscrews and can be easily inspected and cleaned once every 3 months to make sure no buildups have occurred.  Also there are different element coatings that can double the life of the element.  Teflon, epoxy potting, titanium sheath, Incoloy 800 sheath are just some of the options when choosing a replacement element.

Normally these devices cost around $1,000 and they have never been tested in an aquaponic system. Since the jury is still out on the ultimate solution to our water heating,  We will keep you posted on how this proposed solution works once  we get one installed.

  • Dave Coulter

    Curious if you have ever given thought to designing some sort of heat exchanger rather than heating the water directly to combat the maintenance issue with solids? Possible benefits to temp. control / stability as well? Not sure how efficient that would be. Just a passing thought. Perhaps a future experiment for my weekend free time.