STARTING YOUR SYSTEM WITH NO FISH 1. Wash media well before putting into system. Since these are systems for learning, it would be good to try two different media. Of course, the most commonly used is "pea size" gravel. Other options are: coarse sand, pumice, red lava rock (excellent potential since it is light & very porous, large surface area for nitrification), rice hulls (if you do not have rats or mice), sphagnum moss, zeolite, & coconut fiber. One of the problems with gravel & coarse sand is that they can cause some heat build up in the beds during hot weather. 2. After putting media in grow beds, fill with water & start running. If water becomes dirty, refill with fresh. 3. To speed up the establishment of Nitrifying Bacteria in the grow beds, starter bacteria can be purchased from suppliers, such as Aquatic Eco-Systems. For an alternative, you can get some water from another recirculation system or get some farm pond water to add to the system. A quart should be enough. Watercress & possibly some greens can be growing in the beds during this time. They may need some foliar spray or addition of nutrients to the water. Fish emulsion is good. 4. If you want to get the system started without fish, add enough household ammonia to bring the level up to at least 10 mg/l (mg/l is the same as ppm). Continue checking ammonia level. When it starts dropping, it is a sign that Nitrosomonas spp. are becoming established. They oxidize ammonia nitrogen into nitrite nitrogen. This may take two weeks. Check pH. It should be at least 7 for the bacteria to become established. 7.5 is ideal, but hard on some plants if you have them in the system. 5. Begin checking nitrite nitrogen. Many of the initial fish kills occur from nitrite toxicity just after the ammonia drops. The Nitrobacter spp. must become established. This bacteria oxidizes nitrite nitrogen into nitrate nitrogen. This may take two more weeks, depending on water temperature and other conditions. Nitrite is toxic to fish. Nitrate is relatively non-toxic & needed for the plants. 6. Establish a pH close to 7 throughout the operation of the aquaponic system. Check pH early in morning & then during day. Algae blooms can cause pH to increase during the day, especially in water with low alkalinity. Remember that there is 10 times as much toxic ammonia in the water at a pH of 8 as it is at 7. This can cause serious problems. Shade over any open water will help. Dr. Jim Rakocy recommends using potassium hydroxide and calcium hydroxide (hydrated lime) in alternating doses to raise the pH and to provide nutrients for plants (especially fruiting). To lower - sulfuric, nitric or hydrochloric acid. Make a diluted stock solution of acid & water before adding to system. Some have used apple cider vinegar. In addition, since aquaponics systems are deficient in iron, he recommends adding 2mg/l of Iron Chelate (Fe 330) once every three weeks.
7. When fish arrive, check the temperature of the water in the system and fish water. If over 5 degrees F difference, begin to slowly exchange water from one container to the other to get the temperature close to each other. If a big difference (such as 10 degrees), it would be good to allow at least an hour for tempering. Be sure that the little fish have enough aeration. If oxygen is dangerously low, they will come to the surface of the water & begin "gaping". Another alternative that works good for fish that have been shipped is to take the plastic bag with the little fish out of the shipping container. Do not open the bag yet, since it contains oxygen. Immerse it in the fish tank water. When both are close to the same temperature, release the fish in the tank. Do not feed them the first day. 8. A salt bath of 1% for the incoming fish will make them happier. Salt is a stress reliever & will enable them to shed some of the external parasites, which may be present. A salt solution can be established in the container that they are in. For a 1% solution salt, add 10 gr/liter of water (1.34 ounces/gallon). Let them stay in the solution for at least 5 minutes before transferring to the tank. Naturally, you do not want the salt in the aquaponic system. Use salt without iodine. 9. After the system is stabilized & the fish are doing well it may not be necessary to frequently monitor the ammonia & nitrites. 10. Always observe your fish. Do not overfeed. Never feed past the point when the feeding frenzy slows down. If the fish loose their appetite, do not try to feed. Try to determine the problem by water tests, checking how old feed is (do not use feed over 3 months old, unless refrigerated) and observing any external & internal changes of the fish. This is not a "set" way of starting a system. Others vary from the above. Georgia Giant Hybrid Bream are a good choice to begin with, but shipping is expensive. Kenâ€™s # is: 1-800-kenfish. Of course, he also has tilapia. If you want to try pacu, they can be ordered form Schalbach Aquaculture in Florida: 305-2465493. They like temperatures in 80â€™s, but can die below 60. Some people prefer to begin by catching bream from a farm pond before investing in purchased fish. You Will Need For Water Monitoring - ammonia, nitrite, pH, temperature and oxygen are most important. It is helpful to know your hardness. To begin with, the Hach Test Strips or Tetratest Kits on page 85 of the 2006 Aquatic Eco-Systems Catalogue should be sufficient. Their phone # is 1-877-347-4788. If you expand to a larger system, you will want to get more accurate equipment.