It’s that time of year for spring cleaning, time to refresh your aquaponic system and make it more abundant and attractive. Here are ten steps to keep the system going strong and clean.
Manage temperature fluctuations and humidity
Now is the time of year when it might get really hot in the day and still very chilly at night. Temperature management is a tricky one. It is critical to ensure proper air ventilation through the building, circulating air inside the building and managing heat and humidity the best you can. High temperature and humidity can cause plants to bolt and die or quickly succumb to pest pressure and diseases. Give your plants more space, add fans, keep your vines vertical and properly trimmed of suckers and dead leaf material, and choose your crops for heat tolerance so you’ll have greater productivity.
Beat down the bugs
A greenhouse environment allows pests to live year round (unless you choose to grow seasonally). As the days get longer and the crops grow more vigorous, the bugs often grow more out of control. More crop means more to eat and aphids, white flies and other pests love the buffet. The most important thing to do, is stay ahead of the pests. It’s really important to get them while they are young so that they can’t reproduce and make more mouths to feed.
Protect your system from the bigger pests and predators
This time of year, people start opening doors, windows or even moving their systems outdoors to help with the heat. This is also the time of year when birds, squirrels, rabbits, deer, mice, and much more are excited to start checking out your garden spaces and sampling the produce. Fish are very susceptible to becoming sushi dinner from the likes of herons, owls and other birds of prey, bull snakes, raccoons and skunk. Other things to keep watch for, are frogs that want to turn your sump tanks and raft beds into a tadpole nursery.
Keep an eye on nutrients
This time of year, plants are taking up more nutrients since there is longer day length. The pH can plummet quickly if its not being properly adjusted and maintained with alternating calcium and potassium. Iron loving plants like basil and kale will show yellowing (chlorosis) which will cause permanent damage to the plant, so test and supplement iron before the yellowing starts. In addition, vining and fruiting crops needs a wider variety of micro nutrients than leafy greens, so supplementing those crops at the root base and adding phosphorous for blooming, fruiting and flavor are all useful ways to ensure that your plants, bacteria and fish stay healthy and happy.
Improve water quality
If your fish or sump tank water quality could use a bit of a boost, place a submersible pump in the bottom of the tank, and drain out about 1/3 of the water. Apply the water to fruit trees or kickstart your compost. Refill with the tank with temperate, dechlorinated water. This will keep the fish and bacteria happy while removing some of the thicker solids from the bottom of the tank. Too many solids over time will result in larger concentrations of heterotrophic bacteria which consume solids and out compete with nitrifying bacteria for space and oxygen. This will cause denitrification which will reduce the nitrogen available for the plants. Make sure to flush solids out of the system on a predefined basis, keep filters washed, and minimize the amount of overall solids buildup.
Check for thick solids in the media beds and deep water culture
Do your growbeds have a lot of solids in them? Is the bottom of your deep water culture filled with sediment? It may be time for a rinse and refresh. At some point in time, solids will accumulate to a point where they overload the system. When that happens, they can become anaerobic or just too thick for plant roots to absorb anymore. You may have heard that worms help and they do for a while, but they also produce waste. Eventually, the beds just need some cleaning. It's easiest to do this when changing crops out to avoid messing with the mature root systems. Flush the water out of the bed into a bucket or a sump, then siphon or pump out to fruit trees or compost. Try not to wash too much media all at once, since you don’t want to completely disrupt your biofilter in the process.
Clean your pump and pipes
All of the plumbing components and pump in your system can clog with fish solids, bioslime and bacteria. This can put pressure on your pump and make the water flow not as effectively through your system. Remove these components from your system and clean with a blast of water from a hose, a tool like a rifle barrel cleaner or drier cleaning brush depending upon the size of the pipe. At the same time check the pump components to make sure they are in good working order. It might be time to replace the impeller.
As temperatures increase, warm water has less ability to hold oxygen. Therefore it is very important to have clean air stones. Dunk the airstones in a bucket of water and a tablespoon or two of hydrogen peroxide and scrub with a brush to remove bioslime. Also check to make sure that the aerator is performing properly. The bubbles in the tank should be as small and fine as possible for the fish gills and plants roots to absorb them.
Prevent algae and duckweed from taking over
This time of year it is more common to have abundant algae growth. Make sure to keep exposed water covered to prevent unwanted algae that will consume both nutrients and oxygen. Shading fish tanks, sump tanks or any other exposed areas is also necessary to keep algae to a minimum. This may also require adding some new media to the growbeds if there has been significant settling and you have water above the media. If you use duckweed as a feed supplement, it should be grown in a separate container, then sun dried before feeding to the fish. Both algae and duckweed have very fast and prolific lifecycles and can quickly overwhelm your tank water.
Boost good bacteria
Some people shut down their systems over the winter. Others notice changes in ammonia and nitrite conversion with temperature changes. Bacteria are slower to perform below about 60° F and over 80° F. If you are starting up again for the summer, if you did a “deep clean”, you are introducing new fish into the system, or you just need to boost bacteria concentrations overall, it’s a good idea to purchase some nitrifying bacteria to keep the fish safe.
Taking an hour or two for some spring time maintenance can make a world of difference in the beauty and functionality of your aquaponic system. Give it a little love, and it will return an abundance of good clean food.