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What I wish I knew before starting my aquaponic System

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Starting your very own aquaponics system is very exciting and one of the most rewarding feelings is harvesting something that you have grown yourself. Aquaponics is a very sustainable way to grow fruits and vegetables organically and is very simple if you know what you are doing. 

The zeal is there, I know the feeling, but there are some things that you should know before you start your own aquaponic journey and THEY WILL HELP A GREAT DEAL! 

So don’t be like me, learn all the in-betweens that nobody talks about so you can be well prepared for whatever may lie ahead. 

These are the things I wish I knew before I started my aquaponic system.

I would have saved a lot of TIME & MONEY if I knew about these things sooner. 

Don’t get me wrong, aquaponics is a very rewarding pastime and hobby, and scaling it up can bring in a good income. 

See our complete guide on aquaponics and what you need to know to run a successful system.

This article is geared to help you be prepared for everything so you can have a thriving aquaponic system of your own. So let’s do this!

My Aquaponic setup

Additional Nutrients is Required

In aquaponics, we have learned that plants and fishes live together and form a symbiotic relationship where they both benefit from each other.

The Fishes provide nutrients for the plants from their waste and the plants reduce the concentration of nitrates which will cause harm to the fish if allowed to build up.

With the right conditions, the system works like a well-oiled machine, plants and fish are healthy, happy and you are filled with a sense of accomplishment.

But is that all? We know that plants require macronutrients to grow which are (N,P,K) in a specific ratio, and other micronutrients such as iron, boron, manganese, etc. Have you ever seen a Miracle grow box? The nutrients are usually something like 20-20-20. Yea, this is actually the ratio of nutrients –

Nitrogen, Phosphorus, and Potash/Potassium or (N,P,K).


The majority of nutrients in Aquaponics come in the form of Nitrogen (N) as Nitrates.

Green leafy plants like Cabbage, Lettuce, pak-choi and cucumbers love this nutrient which is why they grow best in aquaponic systems.

How do the plants get the other nutrients Phosphate and Potassium?


Phosphate is applied directly to the grow beds in the form of rock phosphate in powdered or granular form. It’s the natural form of phosphate and can be obtained at any gardening store.


Potassium is added to an aquaponic system directly to the water in the form of Epsom salt (potassium sulfate) or kelp meal concentrate. It can also be applied in a foliar fashion where the solution of potassium is sprayed directly to the leaves.

So what about the micronutrients?

Micronutrients such as iron, boron, manganese, and other trace elements are also very important for the all-round growth of every plant.


Iron is added to the water in the form of DTPA Iron Chelate (FE-DTPA) and is more effective in a pH range of up to 7.5. This is the most recommended type of soluble iron for aquaponics because the pH range is more forgiving to changes in water quality.

Other nutrients are added based on the nutrients contained in the food which is being fed to the fish. So it is therefore important to look for food that is not only beneficial to the fish but also the plants in the system.

See our post on adding fertilizer to an aquaponic system.

Build a successful system with these affordable equipment from amazon, that I’ve tried & tested on my setup.

Click on the links to see them

Best water pump
Best Water Pump
Best air pump
Best Air Pump
Best air stone
Best Air Stones
GROWNEER 25 Packs 4 Inch Garden Slotted netcups
Plant Net cups
Bio Balls
Bio Filter Medium
API Freshwater Master Test KIT 800-Test
Water Test Kit
The Aquaponic Equipment Essentials that I use

The High Cost of Biofilter Medium

The biofilter plays a very important part in an aquaponic system where the ammonia from the fish’s waste is converted to nitrites and then to nitrates for the plants to use. 

Without the biofilter, this conversion of ammonia to nitrates will be much slower by the fewer bacteria within the system and with the slower conversion, the ammonia concentrations will build to levels that are deadly to the fishes.

The biofilter medium which is the stuff that fills the biofilter is a bit costly. Now medium such as CNZ 50pcs Black Aquarium Fish Tank Filter Bio-Balls Filtration Media does a great job but it costs $16.89 and would take a lot to fill a 55-gallon biofilter barrel. After doing some maths, It would take 63 like these to fill a 55-gallon drum. 

That’s 63 X 16.89 which is $1073.00 That’s a lot of money.

Luckily, I have found a simple way around this. I found some old fishnets made of monofilament material or that’s what the guy at the marina said. The fishnet totally filled the biofilter and provided a large surface area for bacteria to grow. 

Water Quality Changes quite Often and Has to be Monitored 

The water in an aquaponic system goes through many changes in quality. 

Parameters that are monitored are pH, Nitrites, Nitrates, Ammonia, and Conductivity.

The quality of the water can be affected by many factors from the Nitrification process to weather conditions such as extremely hot days and rain.

Nitrification Process

This process slightly reduces the acidity of the water. Since the bacteria are pH sensitive and activity is reduced at pH range below 6.5, it is important to monitor and ensure that the pH is closer to the 7.0 mark.

Rain – Reduces acidity of the water because rainwater itself is slightly acidic. This is why it is recommended that the fish tank be covered.

Hot Days

Hot weather can increase the temperature of the water and this can affect pH and also the amount of dissolved oxygen in the water.

Plant Density

Having too many plants in the system can severely reduce the nutrients in the system, therefore it is recommended that the system is sized properly to accommodate the number of plants you are going to grow.

Fish Population

Since the fishes produce the nutrients for the plants to grow, having too many can overload the system with Nitrates and ammonia, and having too few can leave plants with nitrogen deficiencies. So again this is why properly sizing the system is important.

Water can be monitored by using test kits such as API Aquarium Test Kit. I recommend this kit because it has never failed me over the past four years with multiple successful crops.

Certain Crops can Take Soo Long to Grow

Crops like lettuce and pak-choi take approximately three weeks from planting a seedling to harvesting. This is very exciting expecting short times for harvesting. 

But other crops like cabbage, cauliflower and broccoli can take up to three months to harvest. 

The reason why lettuce, cucumbers and pakchoi harvest time are short is that these plants are nitrogen or nitrates loving plants. 

What I do recommend is planting both long-term crops and short-term crops and see what works best for you. 

Different Crops require Different Levels of Nutrients to Grow

Crops such as lettuce, cucumbers, and Pak Choi love water and require fewer nutrients than broccoli, cabbage, and cauliflower. 

In the case where you are planting more nutrient-demanding crops, the water quality has to be monitored to ensure that there are more nutrients available for the plants in the water. 

Nutrient levels can be monitored by testing the electrical conductivity (EC) of the water. Nutrients release free ions into the water and these free ions conduct electricity.

The EC meter measures the ability of the water to conduct electricity and in turn measures the number of nutrients in the water. 

Don’t Add Wild Fishes to the Fish Tank

It is very exciting to add more fish to an already functional aquaponics system but there are some things to take into consideration when doing this. 

Wild fishes can bring unwanted diseases with them so here you have to be very careful when adding them to your fish tank. 

Additionally, the water they live in may contain other organisms which when added to your system can invade your system. 

This is what happened to my aquaponic system. The water the wild fishes were living in had very small snails that I didn’t notice. 

The snails invaded my system and I had to empty and wash all the components individually. Now that was real pain. Something I will never wish to happen to anyone. 

If you really want to add wild fishes to your system I would suggest that you place the wild fishes in a separate hold container for at least a week to see if they have any disease or invasive company. 

Silicone and the Uniseal is your Best Friend

I can’t stress enough, the value of a uniseal and a tube of aquarium grade silicone. They are especially useful when it comes to sealing water which makes them ideal tools when it comes to aquaponics. 

What is a uniseal?

A uniseal is a rubber ring that seals the connection made when pvc piping is attached to another component in a system made to carry water. 

In this case, it’s an aquaponic system and the uniseal makes a flexible water seal between components and piping. It replaces the bulkhead and it’s very simple to use. 

The silicone is used whenever there are minor leaks in the system. It’s a quick fix that can save a lot of water. 

You can find uniseals on amazon by clicking here.

Don’t Add Little Fishes with Big Fishes

As much as you may think that the fishes in your system are not carnivorous. Think again! Some fishes will easily gulp down smaller, bit size, fishes even if it’s their own. 

I had tilapia in my system, they grew fast and soon started to reproduce. But I didn’t notice. The fishes were eating the babies as fast as they come. 

I learned that tilapia fishes are mouthbrooders meaning that they hatch their eggs and keep the fingerlings in their mouth until they are ready to leave. Unfortunately, the other larger fishes see this as an opportunity for a quick meal. 

This is why it’s important to notice the signs of the brooding females and remove them from the tank before the fishes emerge. 

This leads to the next point. 

Remove Pregnant Females from the Fish tank

Apart from the fingerlings being eaten by the larger fishes. They can become a real pain to find if you don’t remove the female in time. 

The larger fishes don’t always get a hold on the smaller ones. They sometimes find themselves in all the small crevices and live there until they grow bigger. 

Some of them even go with the water flow and find themselves all over the system where they eventually grow bigger. 

This becomes a problem because if they end up in the sump, where the pump is, they can become caught in the suction causing the pump to stop pumping and halting the entire system. 

This has happened to me before and I have found baby fishes in the mechanical filter, biofilter, plant system within the 4† pipes, and even the sump. 

The Importance of Having a Mechanical Filter

When I first started my system I didn’t have a mechanical filter. Their system functioned really well for the first two months. 

Two months is a long time with 50 fish without things getting a bit messy. But then the fishes were small and then they grew and produced more waste. In no time the biofilter was filled with heavy waste. 

It even carried across to the plants and the root started to look brown as they were covered in fish waste. 

I cleaned the system and installed a mechanical filter. Now all I needed to do is open the drain at the bottom of the filter every two weeks and remove the heavy stuff. 

The mechanical filter removes most of the heavy waste material produced by the fishes and this protects the rest of the system from being fouled.

It also increases the time between system cleaning where you empty and gives the system a general cleanout. 

Pests can Devastate an Entire Crop

Pests can devastate entire crops and proper pest management is necessary for the success of the system. 

When it comes to pest management you may think of using some type of deadly man-made chemical. But with aquaponics, we want to keep it as organic as possible which is why there are effective organic pest controls. 

On such pest control is the use of neem oil extract works wonders. 

The chelated iron added to the system also acts as a pesticide. 

The soapy foliar spray works for aphids and other leaf attacking insects. 

Biological pesticides like ladybugs addition to the crops can help since the ladybugs will eat the soft-bodied insects such as aphids and mites. 

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