Setting Up A Pond Bio Filter



First you need a pre filter, this filters out the worst of the dirt and keeps the bio filter from getting bogged down with dirt. The pre filter gets cleaned regularly. Next you need a pump large enough for your pond. It should turn over no less then 50% of your pond every hour, in this case more is better. Next is the Bio filter this has the water pumped in from the bottom, the water flows up though the lava and back into the pond. It's simple, first the water is pulled down through the pre filter box filter pad, then through the pump and up through the lava rock. One thing about the pre filter box some times when it gets dirty it will try to float so it's a good idea to put a rock on it. I like the idea of fitting the pump directly to the pre filter without tubing. This helps hold it down too. The filter container either has a grate six inches from the bottom that comes with it, or you can use a milk crate cut down to six inches turned upside down. The tub with the grate has a port under the grate to connect the tubing from the pump. The other tub has no port for the tube so bring the tube in from the top down into the center of the milk crate. Now you’re ready for the lava rock. First rinse it off to remove the lava dust and grit. I use a large pot that I got a small tree in. It has holes in the bottom for the water and dirt to drain out. Once washed put the lava rock in the Bio filter tub and fill about two inches from the bottom of the discharge area. Now it's time to seed your filter. You can use several biological starters available in our Water Garden area. I can't stress enough that you follow all directions, and mark all applications on your calendar so you can keep track of everything you did. You can make your new filter work even harder for you by planting Water Mint, Water Hyacinth or other Water plants in the lava rock. This makes your filter a bio vegetation filter. The roots eat up the waste on the lava rock helping to keep it clean too. Remember this will keep your water clean however it is normal and beneficial for some green algae to grow on the liner and other surfaces it will in fact help keep the water clean too. Something to remember if you have a sick fish treat it in another container. What you use to cure your fish will kill your bio filter Medication is made to kill Bacteria.




What is biological filtration? It is the utilization of live, beneficial organisms in a compact environment to interact with the harmful ammonia, nitrite, phosphorous and organic waste products found in fishponds. These organisms are living bacteria that absorb the waste products into their cells for food and solubilize the solids so they can be readily absorbed. What is a biological filter? It is a container for the media or substrate that the water will flow through and on which the beneficial organisms grow. Each time the water contacts one of these organisms, the bacteria has the opportunity to absorb the ammonia, nitrite, or phosphorous. Thus, the more times the droplet of water passes each organism, the more effectively the organism can remove the toxic waste products.


What takes place inside of a biological filter?


Ammonia is oxidized or broken down to nitrite that in turn is oxidized to nitrate, which is harmless to the fish and animal life in the garden ponds. Simultaneously, the solid organic wastes are being solubilized or dissolved. Biological filters provide the appropriate environment for these processes to take place. In addition to break down of the harmful waste products, the bacterial colony in the filter absorb the phosphorous and nitrogen into their cells to use in the cell's metabolism. If the bacterial colony size is sufficient, all of the free phosphorous and nitrogen will be taken up by the bacteria, thus depriving the free-floating unicellular algae of these important growth nutrients. Without these nutrients, an algae bloom [pea-soup green water] becomes impossible.


What factors determine the efficiency and effectiveness of a biological filter?


Some of these factors determine whether the filter is functional or not. The most critical is temperature. Below 45 degrees Fahrenheit, a biological filter has no apparent biological activity. They act similarly to food placed in a refrigerator. That is, bacteria will not grow in cold, and thus the food in the refrigerator will not be damaged. As temperatures increase, the activity of the organisms increases until 60-62 degrees when the filter becomes 100% functional. Temperature should be kept in mind, particularly in the spring when we are trying to establish our pond filters. At 62 degrees, it will normally take about three weeks for the filter to completely cycle and become fully functional, while at 53 to 55 degrees it will take considerably longer.


Ideally, the pH of ponds should be between 7.0 and 7.8 for full biological action to take place. Below a pH of 7.0, biological action decreases rapidly coming to a halt at pH 6.2. This means that ponds that have become very acidic need to raise the pH to above 7.0. The same phenomenon occurs when the pH rises above 7.8, but the cessation of activity is not as abrupt and the range of activity is greater.


By Richard R. Ashbaugh, President of KOI Unlimited