🦐 Apartment Aquaponics Update | Erin Murphy

About two years ago, my awesome boyfriend John and I set out to create an aquaponics system in our one-bedroom NYC apartment. Since my first post was more of a chronological journal about the build (and we’ve learned A LOT since then), I hope this one will serve as a practical guide for replicating our setup and avoiding our mistakes!

Aquaponics combines aquaculture (breeding, rearing, and harvesting water organisms) with hydroponics (growing plants without soil). Frequently, this is done in large-scale industrial farms where both the plants and animals are raised for food, though there are many thriving online communities of home aquaponics enthusiasts. There are many different kinds of aquaponics systems, but (to the best of my knowledge) they all share the same cycle: fish waste water provides nutrients to plants, which in turn filter the water. Despite the abundance of online resources, when John and I first became interested in setting up a home system, we noticed most examples still used tanks and grow-beds that would be far too large for our NYC apartment. This has motivated us to share our experiences, and we hope that this guide may be useful to others looking to create a similar setup! This guide consists of the following sections:

Our System: a high-level overview of our current system design Recent Improvements: highlights of what we have recently changed compared to our initial build Lessons Learned: mistakes we learned the hard way Step-by-Step Build Guide: if you too want to be a city aquaponics farmer!

Our System Media-Based Continuous Flow We opted for a media-based aquaponics system, which means our plants are housed in a separate grow-bed filled with clay gravel. Water from the tank is pumped through the clay substrate, where the rooted plants filter out nutrients from the fish waste. Additionally, we opted for a continuous-flow system, which means that water is continuously cycled from the tank through the bottom few inches of the media bed before draining out the opposite side of the bed. This is an alternative to a flood & drain system, where a timed pump periodically fills the media bed with water before letting it drain completely. While continuous-flow systems are somewhat limited to edible plants that don’t mind a continuous stream of water past their roots, they also provide a much more stable water and nutrient level for the fish living in the tank.

Fig 1: A final sketch of the design where water is pumped into the clay substrate on the right, and then flows back into the tank on the left. Vertical Design We decided to build a vertical system, where the grow-bed of edible plants was placed above the aquatic tank in order to:

Conserve the amount of space the system took up in our apartment. Reduce the odds of any potential leaks, as any water that leaks from the grow-bed will fall into the tank below. Similarly, we added a second storage tub on the bottom shelf to catch any potential water overflow from the tank. Minimize energy costs, as the water only needs to be pumped a short distance up into the grow-bed, and will then be gravity-fed back into the tank.

We decided to use an industrial metal shelving rack as the foundation of our system; a practical and stable option that can support both the heavy tank and grow-bed. The rack is about 3ft wide and fits inside a spare closet space in our new apartment (a true NYC luxury).

Fig 2: The full system on the shelving rack in our closet. Small Size With similar concerns in mind, we also decided to limit the tank size to 20 gallons, as the grow-bed above also contains an additional ~10 gallons of water. Since a gallon of fresh water weighs roughly 8.34lbs, we estimate this puts the entire weight of the system’s water somewhere between 170 and 250lbs. Considering the weight threshold of the industrial shelving, and given that we live on a high floor in our building, we decided to constrain the system to this size to minimize the flooding risk. The tradeoff of this apartment-scale system is that we can only support a grow-bed of about 3 square feet, and are limited to crops with smaller root systems that don’t require a lot of nutrients (such as leafy greens and herbs). Grow-Bed Our grow-bed consists of clay pebbles and a drainage tube. We recently added a bag of crushed coral as an additional filter within the drainage tube. This helps catch waste, soften any drainage sounds, and adds extra minerals to the water that our shrimp and snails need for healthy molting and shells, respectively.

Currently, we are growing basil, and we just added two ‘Tiny Tim’ dwarf tomato seedlings as an experiment to see if we can support fruiting plants. We’ve previously had success with growing basil, mint, and lettuce plants. Tank & Aquatic Friends Our tank is currently home to MANY (estimated 30-50) neocaridina cherry shrimp and ramshorn snails, which snuck in on some plants and multiply like crazy. We also have a single nerite snail and a feeder guppy. Recent Improvements

Improved drainage: In our original design, we used only a small 1“ PVC pipe with holes drilled into it for drainage. However, we quickly realized it was very easy for this to get clogged with plant roots or debris. To improve the drainage, we switched the top pipe to a 4“ PVC pipe inside the grow-bed and drilled vertical slits around its lower perimeter, which allows for much more water flow than the previous pipe. The bottom pipe is still the original 1“ pipe, but we found that using a small rubber bulkhead fitting works much better at preventing leaks than our previous attempt using sealant. Better pump: Our 250GPH original pump unexpectedly stopped working after our move. However, this turned out to be for the best because we realized that a smaller 160GPH pump worked just as well, while being smaller, quieter, and cheaper. Moved the grow light: Originally, we attached the grow light to the top rack of the shelf. This worked fairly well, but often caused burns on leaves of delicate herbs like our basil. In our setup’s new closet location, we hung the grow light about half a foot higher and have it on a timer to run for 8 hours per day. Our plants are still growing great without any burns or heat damage. Using black tubing: We initially purchased clear tubing to connect the pump to the grow-bed, but it sometimes becomes semi-clogged with algae that thrives under the light. We are planning to replace it soon with black tubing instead.

Lessons Learned

Cycling! When we initially got our tank, we were more focused on the aquaponics research and unfortunately underestimated the fragility of a young fish tank.

We have since learned the value of cycling, and would highly recommend setting up your system for at least a few weeks (to establish healthy bacteria and stabilize the water parameters) before adding any animals. Bigger tank = better: If you have the space for a larger tank, I would highly recommend it. The unfortunate downside of smaller tanks is that any small changes in water quality (for example, if a fish is sick or if you accidentally add too much food) can quickly and negatively impact the entire tank. Larger tanks are generally considered more stable. They can also support more fish, which means more nutrients to grow more plants (or plants that require more nutrients). Success with shrimp, snails, & feeders: If you read my previous post, our tank has previously been home to some classic freshwater fish like harlequin rasboras, neon tetras, and salt & pepper corys. Unfortunately, despite our excellent water parameters and careful parenting, we’ve had quite a bit of bad luck with a parasite problem infecting all of our fish besides our one feeder guppy who had snuck in with our shrimp. We learned the hard way that many of these popular species can have major immunity issues and may be bred in poor conditions. If possible, getting fish from local enthusiasts is both cost-effective and a great way to ensure they are adjusted to your area’s water parameters. Also, less flashy species (like feeder guppies) can still be beautiful and may be more resilient than their flashier cousins. Importance of not overfeeding (especially with travel): Many of our fish ailments began with great intentions when we purchased an automatic feeder prior to a long international trip. However, this device ended up overfeeding our tank, causing a huge algae bloom and terrible water quality. We learned from our local fish store that fish can actually go a few weeks without food in a well-planted tank, and from another enthusiast that “hungry fish are healthy fish.” We’ve since been much more cautious about overfeeding, and our tank has thrived. Better drainage: As discussed above, a bigger drainage pipe in the grow-bed has made maintenance much easier. Planted tank communities rock: There is a fantastic, active planted tank community on Facebook in the NYC area, and we had a great experience swapping some of our overgrown plants for another hobbyist’s neocaridina shrimp, which started our current population.