Small DIY Aquaponics System




About: I enjoy being creative. A drafter in my day job I'm a tinkerer by nature always wanting to know why and how things work and if there is a better way to do it.

This is a small aquaponics system i built so i could experiment with the concept. If it works out well for me I'd love to build a large version of this system but before I do want some working knowledge of how it works and any problems i might encounter before I invest a lot of time, effort, and most importantly $$$ into it. This way was a cheap and easy way to gain that knowledge as well as a fun little project. I also want to see what will grow well in the grow bed.

Step 1: Tools and Materials

First things first! Tools and materials.

1. Drill
2. 3/16", 1/2", 7/8" Drill Bits
3. Hacksaw
4. Pipe Cutter
5. Razor Blade
6. Cutters
7. Thread Seal Tape

1. 15 Gallon Plastic Bin (Grow Bed)
2. 1/2" Irrigation Tubing
3. 2 1/2" Ball Valves
4. 3 1/2" Barb Adapter
5. 1/2" Flex Pipe Tee Insert
6. 1/2" MNPT X Barb 90 Elbow
7. 2 #14 O-Rings
8. 2" PVC Pipe 8 3/4" long piece
9. 2" PVC Cap
10. 1 1/4" PVC Pipe 6 5/8" long piece
11. 1 1/4" PVC Cap
12. 1/2" PVC Pipe 5 5/8" long piece
13. 1/2" Male Adapter
14. 1/2" Female Adapter (Electrical Conduit)
15. 2 1/2" PVC Pipe 3" long piece
16. 2 1/2' 90 Degree Elbows
17. Growing Medium (I used a combo of hydroponic rocks and pea gravel)
18. 30 Gallon Plastic Tote (Fish Tank)
19. Black Plastic Sheeting
20. Plastic Storage Shelves
21. 100 - 130 GPH Submersible Pump

Some of the lengths here are approximate because you have to cut to fit and fine tune the system by taking a little off here and there. Also I had to use an electrical conduit fitting because normal pipe threads are tapered and you can't screw them down all the way. I needed a tight fit to prevent leaks from the grow bed.

Step 2: Building the Automatic Siphon

After doing quite a bit of research on these systems i decided to go with a flood and drain system.  It seems like the easiest system to set up and maintain and once its up and running it will run itself with very little need for intervention on my part. In my long and winding travels through the various websites, PDF's , and videos out there the most reliable way to make this system work was the use of a bell siphon. This consists of a 1/2" diameter pipe (the upstand), the 1 1/4" bell (a capped PVC pipe with crenellations cut in the bottom), and a gravel guard (everything I've read says you want to maintain about a 2:1 ratio in the pipe size). The upstand is inserted into the 1/2" male adapter which passes through a hole in the bottom of the grow bed with an o-ring to prevent leaks from the grow bed. The female adapter attaches to the male adapter from the outside of the grow bed. The drainage assembly made up of the 2 90 degree elbows and 3" long PVC pipes is then inserted into the adapter.

Step 3: The Water Pumping System

The most vital part of the system is the pump. My pump is rated at 180 GPH but since I'm pumping the water up about 2 feet that falls off somewhat . Even with the lower rate it is still to much for my purposes but I put it to use. First I attached the pump to a small paver stone using zip ties to keep it pretty much where i put it in the fish tank. Then comes 1/2" diameter irrigation tubing running from the motor to a barbed tee fitting. To this I attached a small piece of irrigation tubing and a threaded adapter so I could screw on a ball valve. This allows me to divert some of the water flow from the grow bed to the tank adding aeration to the water as well as water movement. To the other barb i attached a longer section of irrigation tubing a threaded adapter a ball valve another threaded adapter more irrigation tubing and a 90 degree elbow fitting. This is for pumping the water into the grow bed. The ball valve is to control the flow of water into the grow bed which is very important for the proper functioning of the siphon.

Step 4: Testing the System

Now for the fun part, seeing your hard work in action. I put the system in its final location, remember moving 25 gallons of water plus 14 gallons of rocks equals a hernia, so you do not want to have to move this. I filled my tank with water and added a water conditioner from the aquarium store to remove the chloramine, if your local water utility uses regular chlorine you can just leave the water out for a couple of days and it will evaporate out on its own. Position your water inlet for the grow bed (mine is held in place with a zip tie) and fill it with your chosen grow medium. Now plug in your pump (be sure to read the instructions that come with your pump) and remember that water and electricity are not friends and when combined most especially not yours! The ball valve for your grow bed needs to be adjusted based on how your siphon is functioning. If the siphon doesn't stop your water flow is to high, if your siphon doesn't start your flow is to low. It takes a few cycles to get this adjusted properly. For mine it fills in 13 1/2 minutes and drains in 1 1/2 minutes. Now is your opportunity to check for leaks and change anything that needs to be before you add fish.

Step 5: Stocking Your System

Almost there! Here I've added 6 broccoli seedlings and a couple of mint cuttings I took plus about 20 small goldfish. I chose the broccoli because its a bit chilly here in Florida right now (65 - 75) and broccoli should do well at these temps. I used goldfish because they are very cheap, I paid $4 for 20, and they are pretty hard to kill. I figured since I don't know anything about fish I'd probably kill quite a few of them. To date, 2 weeks after adding the fish, I've only had one die. I was concerned because the water was quite dirty the first day but has since mostly cleared up so I wouldn't worry about that.

Step 6: Testing the Water

I test my water twice a day with a kit for aquariums I picked up at the pet store. Once in the morning, and once in the evening. You can see in the picture I also keep a log of all my results and make notes about my observations such as water quality, how the fish are doing, and anything else of note. When I first tested my water my pH was about 8.0 but has slowly drifted down to 7.6 in the last 2 weeks. There was also a small amount of ammonia present but that's normal from what I've found in my research. Nitrite and nitrate were both 0. After 2 weeks I got a sudden spike in ammonia so I've stopped feeding the fish until it reduces (that will mean i have beneficial bacteria growth. HOORAY!). Once you're up and running all there is to do is feed the fish, test your water, check to make sure everything is running, and wait till you can harvest fresh veggies.

Step 7: Lessons Learned

Lessons Learned:

1. For aquaponics bigger is probably better. I doubt i could raise any useful quantity of edible fish in this system. At most maybe a couple of tilapia and that's probably pushing it.

2. Use a hydroponic grow medium like Hydroton. It's more expensive but far lighter and easier to work with, also pH neutral.

3. It helps to have an extremely tolerant girlfriend who doesn't mind that you've just built this thing in the living room of your one bedroom apartment and intend to make it a permanent fixture on the balcony (this is probably gonna cost me some flowers at the very least).

4. Do not let your girlfriend see any dead fish as this will result in yet another neccesary order of flowers.

5. Patience is a virtue that I still have not totally mastered.

Total Build Time: 1hr 30min
Daily Maintenance Time: 15min

Total System Cost: $40 (Approx. I used what I had laying around as much as possible.)

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    21 Discussions


    7 years ago on Introduction

    Just a quick update. The ammonia levels in my tank spiked yesterday to around 4 ppm so i changed out about half my water for fresh. Unfortunately I had 2 fish floating this morning. These were the 2 smallest so hopefully there will be no more.


    Question 1 year ago on Step 7

    Great Article. HOw did everything go with this? Specifically the broccoli and Mint? Did you find that they grew at a reasonable pace?


    1 year ago

    Is it possible to use an existing aquarium with built-in pump system? I already have a 40-liter aquarium at home with guppies and sucker fish. Would it be too complicated to re-route the pump through the grow bed? Any suggestions would be much appreciated. Thanks!


    3 years ago

    Nice article. However if you are looking to build an Organic; Aquaponic or Hydroponic vegetable garden. You will need to use "Food Safe Plastic"!

    Food Grade Plastic

    5-gallon ‘food grade’ buckets or container are made of #2 HDPE, and are opaque or mostly opaque which minimizes the amount of light penetration. If the bucket is considered ‘food grade’ it is typically marketed as such and / or labeled “Food Grade”, “Food Safe”, etc. Some food grade buckets or containers will include a cup-and-fork symbol as an indicator. A food-grade bucket or container might also be specifically marked as USDA approved (or FDA or NSF approved).

    The typical ‘blue’ water storage containers or water barrels are also made of high density polyethylene (#2 HDPE) and are marketed as food safe.

    If you will be storing food directly in a plastic bucket or container, or if you will be using the container for drinking water, you might verify the material is food-safe before you purchase.

    Risky Plastics Not Safe for Food and Drink

    These may leach or have hazardous ingredients.

    • #3 PVC (polyvinyl chloride) carcinogens during manufacture and incineration
    • #6 PS (polystyrene) possible carcinogen
    • #7 other (usually polycarbonate, sometimes labeled PC) may leach BPA (Bisphenol-A)

    Be sure to rinse any new plastics first to remove any mold releasing agents.

    For tubing, use food grade or "PETE 1" tubing


    4 years ago

    thanks for sharing this. how long did you let your system cycle before you added fish?


    4 years ago on Introduction

    Total system cost: $40 plus $25 for two bouquets of flowers. :-)


    4 years ago on Step 3

    what kind of plastic bin did you use?

    Add more plants to your system. Plants eat Nitrates(such as ammonia) Try adding more plants to counter the spikes. Aquaponics should be self-sustaining.


    4 years ago

    thanks for sharing! have you thought about adding a swirl filter? It surprised me that your small system is capable of keeping 20 fish alive without a filter.

    I really appreciate your instructional post on DIY aquaponics. This is something that a lot of people are looking for these days. It may not be easy but it is all worth the effort when you have fresh fish and vegetable on the table.


    5 years ago on Step 2

    I also live near Tampa, Fl where did you get your grow bed from?


    6 years ago on Introduction

    So Jeffrey, anything new to report? The fish getting bigger? The plants getting bigger? Just curious because I'm about to set up one similar to yours for my wife's college course.
    Hope it is still going well and you haven't had to spend too much in the way of flowers and such.


    6 years ago on Step 7

    Hey I'm a woman and I'm looking into setting up a small aquaponic system... Heck, my mom is deathly afraid of snakes but I don't mind them at all, as long as they don't bite me. Some woman like fish + reptiles, some don't.

    I am thinking of setting up an aquaponic system and keeping river/pond minnows as bait fish for catching bigger fish. You can have success with dead minnows, fish pieces and cooked shrimp as bait apparently. Heck, I remember keeping small fish and cutting them up as bait with my dad when I was a kid.

    Hope your system works out :) I'm in an apartment too or I would love to try to raise tilapia.. they are soooo good!!


    6 years ago on Introduction

    Interesting article, but quite honestly, i can't follow it. You seem to have a ton of tubes and valbves and what not, but in the end I only see one tube sticking out of the gravel bed. I think a drawing of what tube goes into what other tube and where a ball valve or ring or tubing attaches too would do wonders for the 'abstract vison impaired'


    6 years ago on Introduction

    part of your problem with the ph may be the goldfish. They spew tons tons of ammonia waste, they are a VERY dirty fish. I hate to say it but you may want to consider buying a aquarium charcoal filter and running that sometimes.


    7 years ago on Introduction

    One trick I learnt if not using Hydroton and the water becomes acidic, is to crush egg shells and bury them in the grow medium. The Calcium Carbonate will neutralize the acidic water.

    I have a system close to your size, I struggled to produce good lettuce but was able to get Pak Choi, peppers, tomato with a few Tilapia. I am re-designing my own to include a Sump and actually reduce the flood time to around every hour or so. I found the 15 min flood was actually damaging the roots.


    7 years ago on Step 7

    ive been building and using different aquaponics units for about 3 years now and yours looks like it will work really well, depending on what your growing the gravel bed is the best setup in my opinion, i was getting 2 crops of romaine lettuce in the gravel to every 1 in the dirt.. good luck and happy fishing, ps if your close to the kootenays i might be able to help you out in getting tilapia.

    1 reply

    Reply 7 years ago on Step 7

    Thanks. I'm actually in Tampa, FL so no joy o the fish. I hope to build a much larger system in the 300 gallon range when I get some more space and I've learned all I can from this smaller setup.


    7 years ago on Introduction

    nice.. i definitively want to incorporate fishes in my next hydroponic set up.. check out my hydroponic set up for a cheap way to get lots of plants growing