Aquaponics How-To

Green TomatoA lot of Aquaponics gardeners have mentioned that we all need to learn the basic Aquaponic Gardening Rules of Thumb for DIY Aquaponics. The reason why is because as novices we could use a lot of help with Aquaponics How To without investing a considerable amount of time reading and researching what you should do and what you should not do. I had the honor of working with Doctor Lennard on a compilation of guidelines every novice Aquaponic gardener should know about and it really helped a lot of gardeners all over the world.

Ten years ago Doctor Lennard was a recipient of a Ph.D. in Aquaponics worldwide. This was a degree that not many have acquired. Shortly after, he devised, built and managed Minnamurra Aquaponics. This is a commercial scale Aquaponics system, the very first in Australia. Doctor Lennard comprehensibly writes on Aquaponics how to for both trade journals and scientific journals and he consults worldwide through Aquaponic Solutions.

But always know that not everything we advise here is fixed and unchangeable. There are several exceptions to almost every listed rule under certain circumstances. But they do have a set of generally accepted rules that if you adhere to it will place you on a course that would lead to a successful gardening.

Let’s start with the Aquaponics How-to Tips

Aquaponics System Type

Do you know why a media bed is suggested for new hobby growers? You are probably wondering why not Deep Water Culture or AKA rafts or DWC or NFT?. If you would like to know more about media beds and some important considerations when setting up a new Aquaponic system, you can read an article in our website Getting Started Checklist.

Well to answer that question a media bed has three filtering roles:

  1. Bio-filtration
  2. Mineralization (solids breakdown and return to the water)
  3. Mechanical (the removal of solids)

Since your media bed also functions as the medium where your plants grow, more or less it does everything all in one place making it very convenient.

  • Your media bed also offers better support for your plants it is closely akin to traditional soil gardening because you have an actual media to plant.
  • Building the system is also cost efficient because you will only need a few components
  • It is also easier to learn and understand.
Aquaponics Grow Beds
  • If you want to grow the widest array of plants you will need an industry standard of at least thirty centimeters deep or twelve inches to allow for total filtration. If you would like to determine what kind of plants that grow well in an Aquaponics system read the article from our website Aquaponics Plants.
  • It also has to be made of food safe materials and it should not change the pH level of your system. Once again, we are reminding you to be cautious of concrete.
Aquaponics Fish Tanks
  • If your fish tanks have flexibility then one thousand liters or two hundred fifty gallons or even larger appears to make the most stable Aquaponics system. For beginners, we usually recommend you get larger volumes as this allow more room for errors just in case you make mistakes. Mistakes happen a lot slower when in large volumes.
  • It also has to be made of food safe materials and it should not change the pH level of your system. Once again, we are reminding you to be cautious of concrete.
Stocking Density
  • One pound of fish should be equivalent to ten gallons of system water (.5kg for every twenty to twenty-six liters
  • If you have a new system you can estimate one fish for every five to ten gallons of water. Our Aquaponics Fish article will also guide you on stocking your fish.
Steps You Need to Take for Planning Your System
  1. Know the total grow bed area in square meter or in square feet
  2. From your grow bed area, know the fish weight needed in pounds or in kilograms using our ratio one pound or .5 kilograms for every one square foot or .1 square meter of grow bed surface area. This is assuming that the beds are at least thirty centimeters or twelve inches deep.
  3. Know your fish tank volume from our stocking density guideline above (one pound for every five to ten gallons of fish tank volume or .5 kilograms per twenty to twenty-six liters. If you have small and young fish then you need to reduce the quantity of your plants that it has to be proportion to the size of your fish as well as their corresponding waste production and feed rate.

So assuming that you intend to have a couple of two inches by four inches grow beds then this means you will need sixteen square feet of growing area. If you intend to stock mature weight fish of around sixteen pounds then you will need an eighty to one hundred twelve gallons of fish tank.

Aquaponics Grow Media
  • Your Aquaponics grow media has to be inert. It should not alter the pH of your system and it should not decompose.
  • LECA or Lightweight Expanded Clay Aggregate AKA Hydroton, Gravel, and Lava Rock are the most commonly used media types. But if you opt for gravel do know its source and as much as possible avoid marble and limestone as these could alter your system’s pH level.
Water Flow
  • For your water flow, it should be a requirement that you flood and then drain your grow beds. The draining process pulls the oxygen through the grow beds. The less complicated way to acquire a dependable flood drain system is through a timer. The more complex is through bell siphons yet despite its complexity, these are great options for Aquaponics systems.
  • If let’s say you were able to get a hold of a system that makes use of a timer we suggest that you run it for fifteen minutes on and then forty-five minutes off.
  • You should also flow all the volume of your fish tank through your grow beds hourly as much as possible. So if your pump is on for fifteen minutes every hour and let’s say you have a one hundred gallon tank then you will need at the very least a four hundred gallons per hour pump. You should also consider the lift. The lift is how far you need to move your water against gravity. You also need to use the sliding scale found in the pump packaging to check how much power you need beyond the four hundred gallons per hour.
Starting Your System or “Cycling”
  • Fishless Cycling is strongly recommended owing to the fact that it can develop a strong bacteria base and it also allows you to stock your fish tank to its full extent in just a couple of weeks. Compared to the traditional technique of using fish which usually takes over a month and not to mention this is also very stressful for your fish.
Ammonia, Nitrites, and Nitrates After Cycling
  • Make sure you have a test kit with you so you can accurately measure your Aquaponic system’s level of nitrite, ammonia, pH and nitrate.
  • Your nitrite and ammonia levels should not be more than .75 ppm
  • If you notice your ammonia levels abruptly increasing then you likely have a dead fish in your fish tank.
  • If you notice that your nitrite levels are increased then you might have destroyed the bacteria environment within your system. To prevent this, you can read our article on Aquaponics Cycling to know the proper  procedure of creating a colony of beneficial bacteria within your Aquaponics system.
  • If it so happens that either of those mentioned took place then we suggest you stop feeding your fish right away not until all the levels like nitrate, ammonia and nitrite have stabilized. In severe cases we usually recommend you do a one-third water exchange just to dilute your current solution.
  • Your nitrate levels can shoot up as high as three hundred ppm without inflicting any problem but if the levels rise beyond 300 ppm then you should consider getting another grow bed to your system.
  • Just make sure that you have sufficient amounts of oxygen in your fish tank. You can determine this by using a separate aeration device and by averting a part of the water from draining and flooding your grow beds directly to your fish tank.
  • The only surefire way that you’ll have too much oxygen in your fish tank is if you are blowing your fish out of your tank.
  • If let’s say your fish tank does not have enough oxygen infused in your tank then your fish will be gasping for air at the surface. However, if you reach this point you may have already done irreversible damage to your fish’s respiratory tract.
When Should You Add Plants
  • You can add plants as soon as you have started cycling your system. But know that these plants may not be able to grow well for the next few weeks needed for cycling to take place.
  • If you incorporate Maxicrop Liquid Seaweed to your tank when you are planting (most Australians refer to this as Seasol) at a rate of a one-quart bottle for every two hundred fifty gallons or one thousand liters then your plants will be able to establish themselves a lot quickly. See also our Aquaponics Plants blog post to know how many plants you should grow in your system.
When Can You Add Fish (If You Are Using a Fishless Cycling Technique)
  • You can start adding fish as soon as nitrates are present and the nitrite and ammonia levels have raised and declined below 1.0 ppm.
  • You can buy fish fingerlings from us.
Aquaponics Fish Food
  • We have both high-quality conventional fish feed as well as organic fish feed for different stages of omnivorous fish growth.
  • You can feed your fish as much as they want to eat in the first five minutes, once to three times a day. Adult fish can eat around one percent of its body weight in a day. Fish fry or babies can eat as much as seven percent. But a word of caution, you have to be very careful that you do not overfeed your fish.
  • If you see that your fish are not eating then they are likely stressed, they do not have sufficient amounts of oxygen or the water is already outside the right temperature.
  • Add a fistful of composting red worms for every grow bed as soon as your Aquaponics system is fully cycled and the fish have already been added. If you want to know how to get worms to your grow bed, you can read a post from our website Aquaponic Worms.
  • Your target pH should be neutral around 6.8 to 7.0 in your Aquaponic system. This is a deal between the optimal ranges of the plants, bacteria and fish. For your fish, you need a pH of 6.5 to 8.0. For your plants, you need a pH of around 5.0 to 7.0 and for your bacteria, you will need a pH of 6.0 to 8.0.
  • Test your pH levels every week as much as possible three to four times in a week using your API Freshwater Master Test Kit.
  • During your cycling period expect your pH to rise.
  • But soon after you have cycled your systems your pH will plummet below 7.0 regularly and it will require buffering up. If there is a need for you to lower your pH then it is mostly because of the water source like hard ground water or perhaps because you have a base buffer within your system like the oyster shell, incorrect media, egg shells or shell grit.
  • The best techniques for increasing or buffering pH if it goes below 6.4
  • Builder’s lime or hydrated lime, calcium hydroxide
  • Potassium hydroxide or potash or pearlash or Potassium carbonate or bicarbonate
  • If it is possible you can alternate between the two every time your system requires a pH boost. These can add potassium and calcium both of which are beneficial to your plants.
  • You can buy these compounds in AquaUp pH Raising Kits in small quantities
  • While they work be careful when using natural Calcium Carbonate products like snail shells, seashells, and egg shells. These are not harmful but they take a long period of time to dissolve and alter the pH. Therefore, if you add it you should check your pH levels after two hours and if still nothing has changed and you add more and then all of a sudden your pH shoots up because you have already added too much.
  • The best techniques for lowering your pH level in the order of your choice if it goes beyond 7.6
  • Acids like phosphoric and nitric since your plants can still make use of the phosphate and nitrate produced.
  • We have our own pH Lowering Solution that is made of phosphoric acid.
  • You can use other acids like vinegar (this one is weak), hydrochloric acid (this one is strong) and sulphuric (this one is strong) as your last option. We would like to emphasize that the reason why we said these should be your last option is because if you directly incorporate these into your system it will be very stressful for your fish.
  • Avoid putting anything to your system that contains sodium as this can build up in the long run and these can be very harmful to your plants.
  • Avoid using citric acid because this is anti-bacterial and it will only destroy the bacteria you are trying to build up in your biofilter.