Koi Basics 2

4 - WHAT IS A BIOREACTOR? The purpose of a bioreactor is to provide location for bacteria to grow. These bacteria are responsible for a process know as nitrification. In this process ammonia is changed to nitrite and then into nitrate as the bacteria feed on the first two compounds. Ammonia and nitrite are toxic while nitrate is not. Koi are large animals that produce a lot of waste. 75% of their waste is not feces but ammonia that is released through the gills. As such you need an efficient way to remove that waste. A bioreactor should follow your mechanical filter. The mechanical filter removes solids and particulate debris and thus it requires regular cleaning. If the filter is doing it’s function correctly the water entering the bioreactor is clean, reducing the cleaning interval to months vs. days to weeks. Most pressure filters like the Ultima series combine mechanical and bio into one unit. This may be enough for your system, but it will depend on stocking levels, feeding rates, sun exposure, and debris loading among others. The three main considerations for a bioreactor are maximum surface area, good flow/turnover rates and high oxygen levels. The more surface area of the media inside the bio the more bacteria you will have. Bioreactor media can be a bought or a DIY material. Commercial products available are Japanese and Matala mats, Spring Flo, Bio Balls, and Kaldnes. DIY possibilities include open cell foams, plastics, lava rock, river rock, and coarse sands. In all cases remember that you need to be able to easily remove the product for cleaning or a system needs to be built to backwash it in place. Also the media cannot be so fine as to easily clog which causes the flow to bypass sections of the media. This will cut off oxygen to bacteria, leading to anaerobic activity which releases toxins into the water. 5 - BUY A MASTER WATER TEST KIT - Here’s what to look for. Ammonia - tells you if you bioreactor is keeping up with stocking levels and feeding rate. Nitrite - same as ammonia. In new systems these test tell you if you bioreactor has cycled. Cycled is the term used for the time it takes for the bacteria needed for nitrification to become established. This can be 6 to 8 weeks and is temp dependent. Nitrate or phosphorus - not toxic but in excess will lead to algae bloom. This tells you if you are doing enough water changes. <7 7 >7 pH - acid.....(neutral)........base Slightly above neutral is best, but do not add chemicals or make rapid changes to get to this zone. Koi can tolerate a wide range of pH as long as it is stable at that pH. Ammonia is much more toxic at higher pH, so avoid that combination. Low pH causes the bacteria in you bioreactor to shut down. They process much more ammonia slightly above neutral pH. The only time to intervene in pH is if it is extremely low. Slowly raise it by adding baking soda over a period of several days. Most Master Kits come with very good explanations of what each test is looking for and what it’s presence in your pond means. Take the time to read these in depth. 6 - FEED ENOUGH QUALITY FOOD Koi require 1-3% of there body weight in food each day. That means that a 20 inch 5 pound fish will need about a hand full of food per day for that individual. Spread the food out over 3-5 feeding per day. To build quality mass look at the label for the following. - Protein - 32-35% as a minimum. - Stabilized vitamin C, regular forms of C (ascorbic acid) break down rapidly when exposed to oxygen. Animal proteins should be the first and possibly the second ingredients. These will normally be white fish meal or krill meal. Avoid anything with a high level of starch. It is the glue which holds the pellet together and is largely undigestible by koi. If you want color enhancement, again look for krill or the algae sprilina. Don’t over do the enhancers, about 25% of the total food per day is enough. It is good to choose food from two different manufactures. This gives you a better shot at a complete amino acid profile. Keep your food in a cool dry place but don’t freeze it. Store it in an air tight container. Things to avoid are high temps, exposure to sun light and air. Quality packaging will be vacuum sealed, have a re-sealable top, thick material with no windows. Some will also have an expiration date. -Buy only what you need for a few months at a time. If you buy in bulk do so with a friend or fellow club member so that you use your supply in a reasonable amount of time. These are far from a complete examination of each subject. Hopefully you will find them useful as a starting point. Good Luck Rick References- Associated Koi Clubs of America Koi Health Advisor (KHA) course material Advanced Koi Health, Nick Saint-Erne DVM Koi Health, Erik Johnson DVM Koi Pond Design and Construction, Bert Ballou Koi Pond Filter Design and Construction, AKCA Koi USA Magazine, Water Quality by Ray Jordan