Closed Loop System Aquaponics – Your Ultimate Guide To A

Written ByHoward Parker

Have you ever looked at your beautiful aquarium and thought, “I love this, but the constant water changes are a chore”? Do you wish there was a more natural, sustainable way to keep your fish happy and your water crystal clear?

If you’re nodding along, I’ve got fantastic news for you. Imagine an aquarium that practically cleans itself, all while growing lush, green plants right on top. It sounds like magic, but it’s science, and it’s called aquaponics.

I promise that by the end of this guide, you’ll understand exactly how to create your own beautiful, productive, and eco-friendly closed loop system aquaponics setup. We’ll walk through everything, from the basic science to a step-by-step build, choosing the right fish and plants, and troubleshooting common hiccups along the way. Let’s dive in and build the aquarium of your dreams!

What Exactly Is a Closed Loop System Aquaponics Setup?

Let’s break it down. At its heart, a closed loop system aquaponics setup is a brilliant partnership between fish and plants. Think of it as a tiny, self-contained ecosystem right in your home.

Here’s the simple, beautiful cycle:

  1. Fish Do Their Thing: Your fish swim, eat, and produce waste (ammonia). In a normal tank, this ammonia is toxic and builds up, which is why we do water changes.
  2. Helpful Bacteria Get to Work: But in an aquaponics system, that fish waste becomes a resource! Water from the tank is pumped up to a grow bed filled with plants. Here, beneficial bacteria convert the toxic ammonia first into nitrites, and then into nitrates.
  3. Plants Get a Feast: Nitrates are a superfood for plants! The plant roots absorb these nitrates from the water, using them as a free, all-natural fertilizer to grow big and strong.
  4. Clean Water Returns: By absorbing the nitrates, the plants act as a natural filter. The now clean, purified water flows back down into the aquarium for your fish to enjoy.

This continuous cycle is what makes it a “closed loop.” It’s a perfect example of a sustainable closed loop system aquaponics model, mimicking the brilliant efficiency of nature. You get a healthier aquarium and fresh herbs or veggies as a bonus!

The Amazing Benefits of Closed Loop System Aquaponics

So, why go through the effort of setting one of these up? As someone who has run multiple aquaponics tanks, I can tell you the rewards are huge. This isn’t just a novelty; it’s a smarter way to keep an aquarium.

Here are some of the key benefits of closed loop system aquaponics that you’ll love:

  • Drastically Fewer Water Changes: Because the plants are constantly cleaning the water, you’ll only need to top off water lost to evaporation. Say goodbye to hauling buckets of water every weekend!
  • Healthier Fish and Plants: Your fish get to live in consistently clean water, and your plants get a steady supply of rich nutrients. It’s a win-win that leads to a thriving ecosystem.
  • Grow Your Own Food: Imagine snipping fresh basil for your pasta or lettuce for a salad, grown right on your aquarium. It’s organic, delicious, and incredibly rewarding.
  • A Fantastic Educational Tool: These systems are a living science lesson. They’re perfect for teaching kids (and adults!) about biology, chemistry, and the nitrogen cycle in a fun, hands-on way.
  • It’s Incredibly Eco-Friendly: A closed loop system aquaponics setup uses up to 90% less water than traditional gardening and eliminates the need for chemical fertilizers. You’re creating a tiny slice of sustainability in your living room.

Getting Started: Your Essential Supply Checklist

Ready to build? Don’t worry, you don’t need a degree in engineering. Most of the parts are readily available at pet stores or hardware stores. Here’s a basic checklist to get you started.

For the Aquarium:

  • An Aquarium: A standard 10 or 20-gallon tank is a perfect starting point.
  • Fish: We’ll cover the best types later, but start thinking about what you’d like to keep!
  • Substrate (Optional but Recommended): Gravel or sand for the bottom of your tank. It provides more surface area for beneficial bacteria.
  • A Heater (If Needed): Depending on the fish you choose and your home’s temperature.

For the Aquaponics Part:

  • A Grow Bed: This is the container that sits on top of your aquarium and holds the plants. You can buy pre-made kits or DIY one from a sturdy plastic container.
  • A Small Submersible Pump: Look for a small fountain or aquarium pump with an adjustable flow rate. You’ll need one strong enough to lift water from your tank to the grow bed.
  • Vinyl Tubing: To connect the pump to the grow bed. Make sure it fits your pump’s outlet.
  • Grow Media: This is what the plant roots will grow into. Clay pebbles (LECA) or lava rock are fantastic choices because they are porous and pH neutral. Avoid soil, as it will cloud your tank.
  • Plants: Start with easy seedlings or starter plants like lettuce, basil, or mint.

How to Build Your Closed Loop System Aquaponics: A Step-by-Step Guide

Alright, this is the fun part! This how to closed loop system aquaponics guide will walk you through the assembly. Take your time and enjoy the process.

  1. Step 1: Set Up Your Aquarium

    First, set up your aquarium just like you normally would. Rinse your substrate, add it to the tank, and fill it with dechlorinated water. Install your heater if you’re using one, but don’t turn it on or add fish just yet.

  2. Step 2: Prepare and Position the Grow Bed

    Your grow bed will sit on top of the aquarium lid or on a custom-built frame. You’ll need to create two holes in it: one for the tubing from the pump to bring water in, and another for the water to drain back out into the tank. The drain hole should be larger to prevent overflows. A simple PVC pipe fitting can make a great, reliable drain.

  3. Step 3: Connect the Pump and Tubing

    Place your submersible pump in the aquarium. Attach one end of the vinyl tubing to the pump’s outlet and run the other end up through the “in” hole in your grow bed. Position the tubing so it will distribute water evenly across the grow media once it’s added.

  4. Step 4: Add Grow Media and Test the Flow

    Rinse your grow media (like clay pebbles) thoroughly to remove any dust. Fill the grow bed with the media. Now, plug in your pump! Watch how the water flows into the bed and drains back into the tank. You’re looking for a gentle, steady flow. Adjust the pump’s flow rate or the drain height as needed. Let it run for a while to make sure there are no leaks or overflows. This is a key part of the closed loop system aquaponics care guide—ensuring the mechanics work perfectly before adding life.

  5. Step 5: Cycle Your System and Add Fish

    This step is crucial. Before you add fish, you need to establish the colony of beneficial bacteria that makes the whole system work. This is called “cycling.” You can do this by adding a pinch of fish food to the water every day for a few weeks or by adding a source of pure ammonia. Use an aquarium test kit to monitor ammonia, nitrite, and nitrate levels. Once ammonia and nitrite read zero and you have a reading for nitrates, your system is cycled and ready for fish!

    Don’t worry—these fish are perfect for beginners! Start with a few hardy fish to avoid overwhelming your new biological filter.

  6. Step 6: Add Your Plants

    Once your fish are in and producing waste, it’s time for the final piece of the puzzle. Gently place your plant seedlings into the grow media, making sure their roots are nestled in. The nutrient-rich water will do the rest. Congratulations, you’ve just created a living ecosystem!

Choosing Your Champions: Best Fish and Plants for Your System

The success of your system depends on a good match between your fish and plants. Some are just better suited for this kind of environment than others. Here are some of my go-to recommendations.

Hardy Fish for Aquaponics

You want fish that are tough, adaptable, and produce a decent amount of waste to feed your plants.

  • Guppies, Mollies, or Platies: These livebearers are colorful, active, and very hardy. They are a great choice for smaller 10-20 gallon systems.
  • White Cloud Mountain Minnows: A small, peaceful schooling fish that tolerates a wide range of temperatures, making them ideal if you don’t want to use a heater.
  • Betta Fish: For a small, desktop-sized system (5 gallons minimum), a single Betta can work wonderfully. They are beautiful and don’t produce a massive amount of waste.
  • Goldfish: Use with caution! Goldfish are waste-producing machines, which is great for plants, but they also get very large and need a much bigger tank (think 40+ gallons for one). They are better for larger, more established systems.

Easy-to-Grow Aquaponics Plants

Start with plants that are “light feeders” and grow quickly. These are some of the easiest to get started with.

  • Leafy Greens: Lettuce (especially leaf varieties), spinach, and kale thrive in aquaponics.
  • Herbs: Basil, mint, parsley, and watercress go absolutely wild in these systems. Mint is especially vigorous, so be prepared!
  • Houseplants: Don’t want to grow food? No problem! Pothos, peace lilies, and philodendrons are fantastic at sucking up nitrates and are incredibly low-maintenance. They look beautiful cascading down the side of your tank.

Troubleshooting Common Problems with Closed Loop System Aquaponics

Even with the best planning, you might run into a few bumps. Don’t panic! Here are some common problems with closed loop system aquaponics and how to fix them. Following these closed loop system aquaponics best practices will keep things running smoothly.

Yellowing Leaves on Your Plants

This usually signals a nutrient deficiency, most often iron. Your system might be too new, or you may not have enough fish to produce adequate nutrients. You can supplement with a fish-safe, chelated iron liquid fertilizer.

Algae Blooms in the Tank

Algae loves the same things your plants do: light and nutrients. If you’re seeing an algae bloom, it’s likely due to too much light hitting the water or an imbalance where there are more nutrients than your current plants can use. Try reducing the hours your aquarium light is on or add more fast-growing plants to outcompete the algae.

Pests on Your Plants

Aphids or spider mites can sometimes find their way to your plants. Never use traditional chemical pesticides, as they will harm or kill your fish. Instead, a simple spray of soapy water or an application of neem oil (sprayed carefully on the leaves only) can take care of most pests safely.

Frequently Asked Questions About Closed Loop System Aquaponics

Do I ever need to do a water change?

Much, much less often! In a balanced system, you may only need to do a small (10-15%) water change once every few months just to replenish trace minerals. Your main job will be topping off water that evaporates.

Can I grow any plant in my aquaponics system?

Not quite. Fruiting plants like tomatoes or peppers require a lot more nutrients (and light) than a small aquarium system can typically provide. It’s best to stick with leafy greens, herbs, and houseplants, especially when you’re starting out.

Do I still need a separate aquarium filter?

No! The entire grow bed is your filter. The grow media provides massive surface area for beneficial bacteria (biological filtration), and the plant roots remove the nitrates. It’s an all-in-one, living filtration machine.

Your Aquaponics Adventure Awaits!

You’ve made it! You now have a complete closed loop system aquaponics guide to help you create a thriving, beautiful, and productive ecosystem in your own home.

It might seem like a lot of information at first, but remember to take it one step at a time. The journey of building your system is just as rewarding as the final result. You’re not just setting up another fish tank; you’re creating a living piece of art that works with nature, not against it.

So go gather your supplies, get your hands a little wet, and start building. We at Aquifarm can’t wait to see what you create. Happy fishkeeping, and happy growing!

Howard Parker
Latest posts by Howard Parker (see all)
Related posts
  • Are Aquaponics Good? Your Guide To A Thriving Mini-Ecosystem
  • How Is An Aquaponics System A Sustainable Method – Your Guide To A