Aquaponics uses the fish waste to provide nutrients for the plants, eliminating the need for chemical fertilizers. Aquaponic systems do not have a build-up of waste in the system, (compared to Aquaculture) which causes the water to become toxic due to the nitrites. Aquaponics utilizes this waste, with the natural beneficial bacteria in the grow beds converting the nitrites into nitrates, which the plants then consume as their main nutrient source.
Other benefits are; Localizing food sources and reduced C02 emissions, uses 10% water than conventional gardening, less weeding, less pests, providing clean toxin free fish and produce, while easing the pressure off of the oceans.
PH range for Aquaponics?
The PH in an Aquaponics system should be maintained between 6.8 and 7.2.
The ideal range is 7.0.
In a mature Aquaponics system the PH tends to move down over time. This is a result of the acid byproduct, an action of beneficial bacteria in the AP system. It is a natural part of the process.
When adjusting the PH in your Aquaponics system, it is best to do it in small increments. Large or rapid changes are not recommended and can quickly disrupt the health of your fish and plants, however fish can take a wider range of PH than plants.
Extreme low PH of 5.5 can be detrimental for the fish. They have a mucous membrane covering their body, which is part of their natural health defense system. In low PH conditions this protective membrane can be damaged or destroyed, resulting in sick or dead fish.
If your system reads 7.5 or higher this indicates a PH adjustment is necessary.
Adjusting PH down.
The easiest and safest way is to use lemon juice (fresh squeezed). How much depends on the gallons of water in your AP system.
For example; a 500-gallon AP system uses one whole lemon (added incrementally, we can not stress this enough). Wait 24 hours and take a PH reading. If a decrease is observed, repeat the process.
Adjusting PH upwards.
AP systems tend to be low on three compounds: Iron, Calcium and Potassium. Calcium and Potassium can be supplied to your system in the form of PH adjusters. Builders lime, known as Hydrated lime in some states, provides the Calcium and Eco Rose, a product sold as an organic mildew control, provides the Potassium in the form of Potassium Bicarbonate.
Used alternately they will assist in not only adjusting the PH upwards, but provide minerals for the system. For example in a 500 gallon AP system, use two tablespoons of Hydrated lime dissolved in water for one treatment, and on the next treatment two tablespoons of Eco Rose dissolved in water.
Pour the dissolved mixture into the grow bed and allow it to circulate throughout your AP system. Next day take a PH reading to assess, repeat if necessary.
Remember to make adjustments over time. Do not go with one heavy treatment.