Been wanting to start your own AP system? This will be the article for you. I will discuss water, breeding bacteria, fish, plants, lighting…everything you need – and include links to my favorite sources of information. My favorite site for information is the Aquaponics Community Forum, they have information, an online shop, and a great community to field questions. You will find many references to their site and store in this post. It’s a great place to buy things if you can’t locally source them…but check the links when I mention an item so you know what to look for in your local pond/fish/hardware stores. The first article you should read is here, these are the general rules of thumb for running an AP system…remember, GENERAL rules
The information in my article will mostly discuss what you need to do for an INDOOR system, though many of the principles can be applied to outdoor systems as well. The following information is also based off my success with my own tank over the past year:
- 55 gallon tank filled with about 30 – 35 gallons of water
- 1 lg & 2 small “reverse constant flow” media bed filters and one pocket tower – both use hydroton & lava rock
- a mixture of houseplants including dieffenbachia, spathiphyllum, philodendron, zygocactus, ficus, creeping fig, ivy, java moss, moss, and a tarantula fern – added to the system this spring & summer were a basil plant and a cherry tomato vine (which reached close to 17 ft before cutting it)
- redworms added to the system and living in all filters and in the pocket tower
- temp maintained between 76F & 80F
- pH hovering between 6.2 & 6.6
- one air pump running in the bottom of the lg filter…though this died in the beginning of the summer with no apparent ill effects
- 3 goldfish, 3 clown loaches, a siamese algae eater, 3 cory catfish, 2 dojo loaches, a dozen or so fancy guppies varying in age, pond/red ramshorn/malaysian trumpet snails and cherry shrimp
AP systems are advertised as being chemical free. This is mostly true – but nearly everything in our lives are chemicals. You will see links in this article for products such as “stress coat” and “pH up”, though these are chemicals – they are nothing harmful and are only the most basic substances that can be found in nature and are useful to the system to help the fish and bacteria grow. Although we are trying to recreate mother nature in our tanks, she has several more advantages to balancing her world naturally than we do.
Tank Size & Placement
The most important first step is determining size. Several factors will come into play for this decision. Location, weight, lighting, types of fish you want, type of AP system to use…all these should be considered, but first look at your space. What can you fit comfortably? The bigger tank, the heavier the system if it has to be moved. Can you easily get into and around the tank for maintenance? Is there enough space in & around the tank to build out for growbeds?
You also need to consider weight at this point. Water alone weighs about 8 pounds per gallon (so a 10 gallon tank with nothing else in it but water will already weigh in at 80 lbs) Most floors can handle larger tanks (up to 50/55 gallons) without a second thought. What you need to think about is the stand you are going to put it on. Fish tank stands are built to withstand the weight, other tables aren’t, so choose well and do your research.
Lighting will depend on what you are growing. There are a couple of rules about light & tank placement before even talking about enough lights for plants.
• Fish tanks should NOT be placed in direct light. This will cause not only temperature fluctuations, but temp extremes that can kill both fish & the ecosystem you will be growing.
• The bacteria (nitrobacteria) that you need to grow thrive in darkness, UV light will kill them. Another reason to not have the tank in direct sunlight & to have deeper grow beds…which we will talk about in more detail later.
Lighting for plants
Indoor vegetable gardens are completely possible without additional lighting. Most of you already know I grew a bounty of tomatoes in my window, and I’m in the PNW! Consider what you want to grow…a good number of common houseplants that do well in AP systems (ie: golden pothos, spathiphyllum, philodendron, ficus) will do quite well in a north or east facing window if that is all that you have. South & west facing windows will provide more light to support more plants, but again, the tank itself should not get direct light, just the plants – and some plants can get “burned” in direct light. A west or south facing window will be needed to grow most vegetables – a longer photosynthetic period is needed for these plants to covert enough food & set fruit. Research your plants needs before placement and planting.
Most house plants I’ve used have done quite well with lighting from a “plant” type fluorescent bulb.
You will need the following tools & equipment handy for most tanks:
- Tank – all glass aquariums with silicone seal (its non reactive with the ecosystem) are great. Getting a used one to help recycle is awesome – just be sure it was only used for fish & is cleaned well with a weak bleach solution, then RINSED very well.
- Filter or growbed – please see “filter & growbed” section below
- Pump – you need a quality pump that will move as many gallons as your tank holds per hour (ie: 55 gallons of water should be moved per hour for a 55 gallon tank) You also need to consider the power the pump has to “lift” water, check the pump package for numbers. I used ecopumps, they are cheaper and run well
- Growth substrate – any type of gravel that doesn’t have limestone or marble in it (it can leach out and change pH) I personally use lava rock & hydroton (a type of expanded clay marble) Another great new choice is expanded shale . Click here for more info and pricing on all these. A word on lava rock, it works great and is cheap ($4 for 25 lbs at Home Depot) but requires a lot of rinsing and is hard on hands and roots if moving plants around.
- Flexible tubing – Any type of flexible tubing available in pet or pond stores is suitable for your tank. Most smaller pumps will use a 1/2 inch plastic tubing, black is better than clear.
- Air Pump – It will benefit most tanks to have an air pump going, detailed reasons will be discussed further in the article.
- Testing kit – don’t skimp on this one. You can find test strips…but they OFTEN give false readings. Save up and buy a Freshwater Test Kit for your system. It can help you decipher what is happening in your tank.
These are the basics you need to get started for any system. The rest of this article will discuss in further detail what you need to run your system.
Why? All AP systems are dependent on O2, more precisely, dissolved O2. The only way to get O2 dissolved in the water is to move the water around, a lot. It also helps the O2 gas exchange when a large surface area of water is exposed to the air. Also, cooler water holds more O2 than warmer water.
A well placed air pump + air stone doesn’t work by dissolving O2 into the water from the tiny bubbles it produces, but rather helps to move the water continually up to the surface and creates a flow + enlarged surface area by breaking the surface tension. This system is a great O2 back up as well if the water pump goes down for a while.
Filter & Growbed
There are many ways to build a grow bed for your system. Most systems use either an “ebb & flow” or “constant flow” in media beds, or “NFT/DWC” (nutrient film technique/deep water culture) system. Quick explanations of each of these here. Please check the forums here or google for more information on these terms, be sure to include the word aquaponics when googling.
I want to talk about my filters. I am using a sort of “reverse constant flow” for all my tanks. The design is simple and has several advantages:
- It is more compact that traditional AP growbeds
- Because these filters sit IN the tank, there is little chance of leaks that can drain your tank/kill your fish/ruin your apartment or home
- Based on my year of experimentation this system seems to be just as effective as the two traditional methods
- Due to their smaller size, these systems are more removable/transportable/cleanable should the need arise
These systems, as do all, also have some disadvantages:
- Small size means smaller grow bed area = less room to grow more plants
- Because these filters reside in the tank, they take up space in your tank that could be used for fish or additional water for added system stability (read more about this in “water” section)
- smaller tank size indoors means it is harder to grow fish for food
The construction is rather simple. I like to use the biggest & thickest glass (it is inert) vases I can find. In the bottom of the vase run a tube, which will attach to the pump in the tank, coming up and over the top. Making the tube/connection to the pump easily detachable makes it much easier to do maintenance when/if needed. You can also add an airstone with tubing attached to it to go to the air pump. Remember to make a removable connection where it comes out of the vase so it can be disassembled if needed.
The next step is to fill the vase with your pre-washed grow media. I plan on building future filters by first finding a net pot or similar basket large enough to fit inside my vase, then filling the net pot with grow media. This will allow you to easily lift the pot out in the event you need to replace the tubing, the vase, the airstone or work on your plants.
Plants can now be planted in the media bed to filter the water for your fish. Once the pump is turned on, water & fish waste will be pumped to the bottom of the filter and travel up. Solids will slowly collect in the media and on the roots as it is broken down by nitrobacteria and made into food for the plants. As the water travels to the top, it spills out and back into the tank – filtered of toxins called nitrites & nitrates and renewing its dissolved O2.
I do not have any scientific evidence to back up the benefit of the airpump, but I took a hint from NFT/DWC systems who place air pumps in the bottom of the water trough that plant roots sit in. The air bubbles collect on the roots, helping to provide additional O2 when solids start to build up on them. I found my filters seemed healthier during the first 8 months or so of maturing time. My pump has since stopped working, but I have seen no decline, possibly due to the maturity of the system.
Water, Chemistry & the Nitrogen Cycle
Water is the life of your system. It carries O2 to fish for breathing, to bacteria so they can breakdown compounds, and to plants in the evening so they can finish the photosynthesis cycle. Water also dissolves minerals to help regulate pH & it keeps temperature from fluctuating too rapidly.
The more water you can have in the system, the more stable it will be (this is called its buffering capacity) – although I can state with absolute certainty that you can have a successful AP system with just 2.5 gallons of water. The dangers you are more likely to face with smaller systems are swinging pH, temperature, and low dissolved O2.
Water is also the home of your bacteria. More specifically your Nitrosomonas and Nitrobacter bacteria. These bacteria complete the nitrogen cycle that must thrive in your tank in order for AP to be successful.
The nitrogen cycle works like this: Organic compounds (fish waste, left over fish food, rotting plant bits, dead animals) break down into ammonia. Nitrosomonas & Nitrobacter are found in small numbers all over your tank, but the Nitrosomonas bacteria begin to flourish when ammonia levels rise. They feed on ammonia and convert it into nitrites. Nitrobacter then begin to flourish as they convert the nitrites into nitrates. As the dissolved nitrates are pumped into your grow beds, the plant roots absorb them and use them as food. The ammonia, nitrites & nitrates have now all been filtered out of the water by your bacteria/plants, and as long as you have good flow the O2 is replaced and is now a healthy environment for your fish. Your fish create waste and the cycle begins again.
Criteria for your bacteria to flourish:
- A temperature between 60F & 86F, anything on the extremes and they will begin to die
- The bacteria like the dark places of your tank – UV light kills them (corners, under gravel, and deep in growbeds)
- There must be porous surfaces for them to grow on (your bed media)…they can not thrive in the water column
- Presence of ammonia to start the cycle
- a pH between 6 & 8
Where you want your temperature & pH lie will depend on what kind of fish and plants you want to grow. Do some research to see who matches best with what. Also remember to get a test kit so you can track changes in the nitrite, nitrate, ammonia & pH levels…these levels tell you many things about what is happening in your system and what you need to do to adjust them.
Chlorine & Chloramines
Cities use either chlorine or chloramine to treat our water. Both chemicals are bad for your fish and for your bacteria – they will cause death. Be sure to check your local city water treatment plant (details usually available online) to see what they use. If it is chlorine, you can let water sit out for 48 hours and the chlorine will dissipate and be safe to add. Chloramine does not dissipate and remains dangerous without treatment.
There are water conditioners to treat chlorine (NOT chloramine) you can add to a home system that don’t pose a threat…though try to only use them in a pinch if there is no time to degas the chlorine if you plan on eating veggies from the system. There is no hard evidence of it effecting humans or getting into the veggies…but better to err on the side of caution. For a houseplant only tank, it is fine to use every time you add water.
I am not an expert on getting rid of chloramines as I don’t have them in my water supply. Take a look at this forum thread for some ideas and some other links to read on the subject.
Cycling your tank – making a happy home for fish & bacteria
There are two ways to cycle your tank, which means getting the nitrogen cycle started. With fish and without.
Cycling your tank with fish involves having the whole system set up and adding fish. You feed them just a bit each day. Their waste creates ammonia, which starts the cycle. This, however, can be quite stressful on fish as the presence of ammonia & nitrites are harmful to fish – they could become sick or die. Some species of fish really don’t seem to care, but it is still a risk.
You can also cycle without fish. I started by planting some plants in the system and letting it run. The decaying roots on the plants caused the ammonia spike for me. You can see a white, milky clouding and slight thickening of the water when this happens. This starts to clear as the first batch of bacteria grow and as the ammonia spike lowers it cause a nitrite spike. The second batch of bacteria then start to bloom and there is a lowering of nitrites and an increase in nitrates – then the plants can start to feed and grow. Nitrates are not nearly as dangerous to fish, unless there is long-term exposure, so this is a good place to start adding fish. Again, this is why testing is important to see where your cycle is at and when it is safe to add fish.
Always add fish and increase feeding SLOWLY. The resulting rise in waste can cause another ammonia spike, and your system, especially when new, needs time to catch up.
Other people start by adding pure ammonia (without any surfactants in them) instead of waiting for organic material to start to rot. Check out this forum topic and read up on different styles and products people use to get the job done, then decide what you are comfortable with what works for you.
Water Pump & Flow
As mentioned before, water flow & agitation of the surface means increased O2 levels and complete support for the life of your system. Look at water pumps that will move the entire volume of water in your tank every hour. You also need to look at the back of the box on the pump to see how high it can lift water. For example, my pocket tower is 3 ft high and is on a 6 inch riser in my tank. The pump I bought for it needs to easily lift water 4 ft and be able to move at least 35 gallons of water per hour. It is easy to take a moment and check, and worth avoiding the frustration.
Take a look at this article I wrote awhile ago about vermiponics, adding redworms to your system, for the advantages of trying it, plus some rules for adding them. A note on timing, don’t add them too early to a system. The worms need to eat. They eat fish poo, bacteria & decaying plant matter. In a new system (which I might classify as under 9 months) there may not be enough food to keep the worms alive.
The worms also make a nice way to compost veggie matter. During the growing season of my tomato vine I would chop up any leaves or stems that I pruned and put it in the top of my pocket tower. Within a couple of days the worms would have devoured everything.
What fish to use?
It is a personal choice. The great thing about AP systems is being able to grow edible plants AND fish. The downfall of indoor AP systems is you are usually limited to veggies as growing a bunch of edible fish means you need a lot of room to grow them. I would stick to ornamental fish when staying inside. Goldfish are a great, cheap choice for making a dirty tank (remember you NEED waste to keep the system going) and don’t need a heater in a home that stays a fairly constant temp. They are, however, fairly aggressive if there are smaller fish (they eat baby guppies) and will most likely destroy any plants planted directly in the gravel bed unless they are big and established.
Also think about the max size of the fish when full-grown – this will help dictate what you can use.
Remember you can use just houseplants in your system if you would like to just have pet fish in a tank that uses few chemicals, is cheaper to start & maintain, and will be a beautiful addition to your home. The plants I have been successful with are dieffenbachia, spathiphyllum, philodendron, zygocactus, ficus, creeping fig, ivy, java moss, moss, and tarantula fern. I’ve included links so you can see what they look like and get some detailed info on them. You can experiment with others and see what does well for you. This winter I am attempting to use several different species of stonecrop plants, cacti & succulents.
Almost any veggie can be grown depending on light & room. I had wonderful luck with tomatoes, lettuce & basil in my pocket tower – next year will be heirloom tomatoes, cucumbers, peppers & herbs. Most grow fine together, some have special needs. Leafy greens are the easiest, veggies and fruit require a little more attention to the tank, and require a more mature tank. (see “tank maturity” below) There are even people growing citrus trees, LOL, which I don’t have room for. Check out this forum link and google some AP veggie topics before planting.
Tank maturity & maintenance
A new system will have very little food to offer your plants. As a tank matures, the cycle of ammonia -> nitrites -> nitrates happens very efficiently and can support the needs of hungry plants, ie: vegetables. I didn’t consider my tank mature until it was about 9 months old. The readings seemed to stay stable, the water took on an amber tint (all AP systems do this as they age) and everything was absolutely BOOMING in growth. Leaf size on some plants were HUGE.
Watch your tank, learn your fish & plant behavior. You will notice when things seem to be working better. (this is also a good time to add a boost with the worms) You can plant veggies before the tank is mature – in fact, you have to plant SOMETHING for the system to work, though you may not get immediate, big results. Try using houseplants first, then replacing them with or adding in veggies once mature.
You will also notice that as time goes on, your even level of pH will start to slowly drop toward 6. This is a natural effect of a good AP system. (from what I understand, decaying matter naturally causes a drop in pH, though I don’t know why) This is an easy fix with a product called pH up. It contains potassium hydroxide & potassium carbonate – all safe & beneficial for fish and plants. These substances would normally be replaced in the wild by slowly leaching from rock…so we occasionally need to provide them to our tanks.
There is less maintenance than a traditional fish tank. Though people usually become so entranced with their systems it doesn’t matter and they always have their hands in it. There are NO monthly water changes or vacuuming needed! It will actually hurt your tank to do so. The fish waste is USED by the system to maintain balance. The only time you add water is when it evaporates. If you seem to have an ammonia spike in your tank – you don’t need to change water or add a neutralizer, you simply need to reduce feeding to your fish. The less waste they produce and less leftover food in the tank means less ammonia being produced. With an ammonia spike also comes a spike in bacteria growth, which only strengthens your system.
Learn to take readings of and understand what the levels of ammonia, nitrites, nitrates, & pH mean and how they interact with one another and you can easily change the conditions of your tank by knowing when to wait changes out and when to act.
As a tank matures, you may have to wipe some algae growth from the glass – which can also be an indicator of too high a fish ratio to plants if it’s out of control. You may also have to occasionally rinse out any pre filter sponges you have IF they clog. Remember not to use untreated tap water as a colony of bacteria will live in the sponges and chlorine will kill them. The dirty water from rinsing them is great to use on houseplants.
Other than that & maybe some occasional pruning, the system if fairly self-sustaining.
Have fun building and maintaining your tank! Use your imagination and experiment with your own design while using the general rules as a guide. Look at your tank everyday to learn what is normal behavior for your fish and plants so you can recognize problems if they arise later on. Remember to always look things up if you don’t know and reach out to forums full of people doing the same thing you are. Someone has probably had your same problem before with a fix for it.
If you have questions or comments, I’d love to hear them! Live in the seattle area and want to start one, but need personal help? Contact me & we can talk details.