Water quality, unhappy plants, fish troubles, and pest-control tend to be the problematic areas for aquaponic farmers. Plants can become sickly and die for a wide variety of reasons including insufficient water, or insufficient concentrations of dissolved oxygen, iron, or other minerals. Plants will also do worse in more alkaline water, and prefer a slightly more acidic pH level. Ideally, your water will be between 6.5 and 7.2. Overcrowding in your fish tank will also quickly decrease your system's conditions and efficiency. Excess fish waste will not be filtered by the plants, and can make the water toxic for the fish inside.
Just like in regular agriculture, pests are an irritating but natural part of growing crops. Adding pesticides would be harmful to your fish, bacteria, and entire system. Therefore, natural remedies for aquaponic pests, like neem oil, are commonly used instead. Aphids, caterpillars, and other insects are commonly found in aquaponics, and can be removed by hand with frequent visual checks. Alternatively, bug netting can create a physical barrier around your plants to prevent pests from being able to access them.