Aquaponics How To

This depends on what type of fish you have in your system. There are fish foods specifically for certain fish and others eat the general fish food. Fish food can be in the form of live worms and snails or packaged fish food. We use Ridleys.

In a home system we feel that you should feed your fish morning and night. As close to 12 hours apart as possible.

Firstly test the water. If you can not do that or you get a very high reading of Ammonia or Nitrite then we suggest you release about one-third of your water and top up your system up again. If you have tested it and the Ammonia and Nitrite are not too high then stop feeding the fish for a couple of days. They will survive without feeding for a few days and the water should clear. After either of the above review how much you are feeding your fish as you are probably overfeeding them. Remember that when the water temperature drops the fish will eat less.

The amount will vary depending on the type of fish, the temperature of the water and the type of food you have. The general rule in warm weather with commercial fish food is about 3% of their body weight when they are small fingerlings and about 1% of their body weight once they are no longer fingerlings. Most people grossly overfeed their fish so please weigh your feed when you first start. This will give you a good idea of how much you are feeding the fish.

Anti-bacterial treatments will also kill the Ammonia-oxidizing-bacteria and the Nitrite-oxidizing-bacteria. Obviously this is not good as it will stop the nitrication process.

A bacterial Bacillus thuringiensis (Bt) is used to control caterpillars in some commercial and experiemental systems. Yates 'DIPEL' product contains the bacterial. Garlic spray can be used as a repellent and to kill caterpillars if you do not want to use Bt. Also there are many other 'organic' methods that you can try.

We find that removing the effected leafs and spraying milk on the remaining leaves works very well for us. The milk spray is 1 part fresh milk and 4 parts water. It will help control the fungus and will not kill fungus eating Lady Birds. You may need to spray weekly.

If your plants are starting to go yellow it is most likely because your system is low in Iron. Add some Chelated Iron to your system. A teaspoon of Chelated Iron mixed in a bucket of water and added slowly into your grow beds should do the trick. You might notice your system goes black or very dark in colour after you do this. That is fine, don't worry about it and it will clear in a few days.

Most chemical pesticides will kill the fish.

Generally no. So long as you do not overstock with fish and keep monitoring your system for pH, Ammonia, Nitrite and Nitrate.

You should get a test kit that does pH, Ammonia, Nitrite and Nitrate. What you should see, after you put the fish into the system, is an increase in Ammonia. The Ammonia should keep increasing. Over this time Ammonia-oxidizing-bacteria (AOB) will commence to multiply. They are typically slow to multiply. Once there are enough AOB the Ammonia should decrease. This should start within one and half to two weeks. Nitrite should now start to increase in the system as AOB convert the Ammonia. As the Nitrite levels increase the Nitrite-oxidizing-bacteria (NOB) will begin to multiply in the system and the Nitrate level will start to increase. NOB are equally slow growing bacteria and it will typically take a week and half to two weeks before the Nitrite level will peak and then start to decrease. By now, if everything is going well, the Ammonia should be very low and remain like that. Nitrite levels should continue to drop over the next few weeks until it remains at a low level. Nitrate levels will vary depending on the balance of fish and plants in the system. pH should decrease over the period as the nitrification process will make the water more acidic. Keep a track of this. pH must be above 7 for the nitrification process to work properly.

Yes, it is very important because Ammonia and Nitrite are very toxic to fish. Nitrate is not as toxic to fish and the plants can use it to produce protien and nucleic acids.

This is usually ok and you do not have to do anything to 'fix' it. The nitrification process will cause the system to become more acidic over time. We have had systems with pH levels just over 8 when they started and they all went down over time.

It is normal for the system to get more acidic. The problem is that below 7.0 the nitrification process will start to slow.  The slowing is dramatic by the low 6's. It is important that you do not let this happen! You can increase the pH of the system (make it more Alkaline) by adding Calcium Hydroxide [ Ca(OH)2 ] "Hydrated Lime" or Potassium Hydroxide [ KOH ] "Caustic Potash". In both cases be very careful. Add a small amount of the powder to a bucket of water. Then pour it into your system slowly over a prolonged period (like a day). Remember it is very Alkaline so do not just dump it all quickly into the system.

Note: Calcium Hydroxide is reasonably safe however Potassium Hydroxide is not. Both however should be handled with care.

There is no 'normal' pH in an Aquaponic system as such. The pH level will change over time depending on the system and how it is running. The system will not settle on a particular pH and stay there. This is why it is a good idea to test the pH at least once a week.

pH is a measure of the degree of the acidity or the alkalinity of a solution as measured on a scale (the 'pH scale') of 0 to 14. Technically it is a measure of the activity of the hydrogen ion (H+). The midpoint of 7.0 on the pH scale represents neutrality. pH 7.0 is called a 'neutral' solution and is neither acid or alkaline. Numbers below 7.0 are known as acid. Numbers greater than 7.0 are known as alkaline.

The pH in an aquaponic system should be maintained between 6.8 and 7.2.

The process whereby Ammonia in wastewater is oxidized to Nitrite and then to Nitrate by bacterial or chemical reactions. Basically there are Ammonia-oxidizing bacteria (AOB) that convert Ammonia into Nitrite in the presence of oxygen for energy. Nitrosomonas is an AOB. Then Nitrite-oxidizing bacteria (NOB) convert Nitrite to Nitrate in the presence of oxygen for engergy. The most common mentioned NOB is Nitrobacter however some modern studies suggest that Nitrospira is perhaps a more important NOB.

The concept of grown plants on top of fish ponds is not new.  A model called a 'hydroponic solar pond' was talked about and designed by Ron Zweig and the people at New Alchemy Institute from about the mid-1970's.  Of course they were probably not the first to think of or design such a system but they are the first ones to document it that we know of.  If you search the web you should find information about the design.