UGF (Under Gravel Filter) Maintenance Procedure
The advent of the under gravel biological filter, revolutionized the hobby of keeping and maintaining healthy fish aquaria. Due to it's low cost and superb performance it soon became the mainstay of the aquarium industry and because of it's ease of use and popularity is still here with us today, holding it's own in sales amid the myriad of newer biological filtration methods.
The Under Gravel Filter when used in conjunction with almost any type of effective mechanical filtration device available, insures that not only will your aquarium be a great success, but moreover the tanks inhabitants will live a long and happy life.
In recent years, a new problem has seemed to have arisen, that was totally unheard of in the aquarium industry before. Needless to say, the total blame has been placed by aquarists on the UGFs, which have up to now, worked so remarkably that it is almost impossible to consider setting up an aquarium without one.
The answer is very simple! Over the years, the average particulate size of the substrates used by aquarists has steadily decreased, from the larger road size gravel, around which the original UGFs were designed, down to pea size gravel and from the larger decorative quartz pebbles common for so many years, to tiny artificially colored coarse sand size substrates. Even today, the trend is to reduce substrate size even further, to the finer sand substrates as used by reef keepers in a Natural Nitrate Reduction system.
With the growing popularity in marine and reef environments, the UGF has gone by the wayside for more elaborate and expensive bio-filtration techniques which, in many cases, are still yet unable to prove their worth, especially in a mini-reef aquarium set-up where nitrates should be kept as close to zero as possible.
The increasing popularity of the Natural Nitrate Reduction systems or to some the Jaubert Plenum, combined with the fear of trying an unproven system that is constantly bordering on the possibility of total disaster for the aquariums inhabitants, has caused many aquarists to take a new look at the tried and true UGF, to replace the egg-crate form currently being utilized in the Jaubert Plenum.
The scope of this article however, is only to re-enlighten aquarists in the lost art of cleaning and maintaining the simple yet versatile UGF. Many years ago, the proper way to clean and maintain a UGF was clearly printed on every package. Over the years, lack of proper filter maintenance seemed to cause little if any problems in freshwater aquaria, therefore manufacturers began to drop the cleaning and maintenance instructions from their packages.
Today, more than ever before, we are maintaining the most delicate of species, requiring a more rigorous maintenance schedule. Test kits are now available to determine almost every parameter of your water chemistry. Poor maintenance of the UGF and mechanical filtration systems of your aquarium, readily appear as elevated levels of dissolved organic carbons long before pH levels begin to decline.
The end result of believing that there is no required maintenance of UGFs, that the proper sized substrate is of little importance, and no external mechanical filtration is required, leads many an aquarist down the road to doom. It is these very same aquarists who continually complain about their problems and blame it on the Under Gravel Filter, rather than their own ineptitude. They spread dreadful tales about how bad UGFs are at mechanical filtration (not a function of UGF filtration) and often hear of them shifting or sifting their filthy undersized gravel all around the aquarium and lifting uncleaned UGF plates, filling the entire aquarium with the debris from under their grossly under-maintained and improperly set-up systems. Sorry to sound so harsh, but it's a fact!
Modern UGFs now have large diameter lift tubes, making them even easier to maintain and keep clean. The large diameter lift tubes also affords the opportunity to keep your substrate reasonably clean as well. Following these simple procedures outlined below.
To clean a UGF filter, first remove the directing cap and charcoal filter cartridge, if so equipped. Remove the airline and airstone from each of the lift tubes. Using a soft piece of tubing about 3 to 4 feet long, construct a syphon that just fits into the lift tube. But not so snug that you may possibly pull the lift tube from it's mount. You can size a smaller piece of syphon hose by wrapping black electrical tape around the end till it just barely fits into the lift tube.
While you are cleaning the UGFs allow your airstones to soak in a Hydrogen Peroxide bath to help clean them. Better yet, replace your airstones on a regular basis and especially after cleaning your UGF.
Place the taped end of your syphon hose into one of the lift tubes and start the syphon to flow. Using your thumb or finger, stop the flow of water from the output side of the syphon hose. While holding the stopped syphon, pump vigorously up and down in the lift tube with the syphon hose. After doing this about 4 or 5 good plunges, release the output into the catch bucket and watch the gunk pour out. Repeat this step for each lift tube in your aquarium.
Now, go back to the first lift tube, only this time, after starting the syphon and stopping it as described in the previous paragraph, pump very vigorously with great emphasis on the word very. You are trying to loosen any debris trapped in your substrate, so full rapid plunges are desired. Release the output and you should obtain another batch of brown gunk, just as in the first step. As before, repeat this step for each lift tube.
Replace your airstone, airline, cap, and replenish your carbon cartridge if you elect to continue the use this item, with new, well rinsed carbon. Top your aquarium back up with prepared water suitable for your particular aquarium. Turn you air back on and balance the airflow between the lift tubes. 1 to 2 ml/l is more than sufficient airflow into the lift tubes.
On freshwater aquaria, if you perform this step at least once every three months or less, you will notice a remarkable improvement, not only in the quality of your water, but in the health of your animals and plants as well.
In marine aquariums utilizing UGF plates, I recommend cleaning your UGF at least once per month and maintain an airflow that does not exceed 1 ml/l into the lift tubes. I do not recommend UGFs to be used as UGFs per se in any reef aquaria, except as a means to remove detritus, should the need arise. UGF plates are an excellent alternative to eggcrate diffusers in Natural Nitrate Reduction Systems.
In addition, these few notes may be beneficial to all aquarists! In freshwater aquaria, use a substrate that is proportional to the size fish you plan to maintain. If you side toward the larger specimens, it would be wise to use a substrate that measures 1/2 to 3/4 inch diameter with some smaller particulates mixed in. This allows the larger feces from such fish to fall below and between the pebbles so it will be consumed by bacteria at a faster rate.
For a regular community tank with no large specimens, 3/8 to 1/2 inch substrate would be a better choice, but don't get to fine as the substrate will become more of a mechanical filter than a bio-filter. This is not to say that smaller material is not bio-active, only that the filter becomes mechanical and traps detritus.
In marine aquariums, the use of whole puca shells or larger sized crushed shells have been commonplace in systems utilizing UGFs. The trend toward smaller sized substrates shows that these smaller materials have a tendency to layer themselves restricting water flow through the substrate and the filter becomes mechanical. Thus the substrate should be agitated as often as possible, either manually or by the addition of animals that will perform this function for you.
In reef aquaria, numerous animals are available for agitating the substrate as mentioned above. One advantage of utilizing capped UGF plates in a reef aquaria is that you do not end up with dead areas under your live base rock formations where anaerobic bacteria may form, causing the dreaded wipe-out syndrome. Detritus can more readily be removed from the substrate without syphoning out your little micro-animals from the substrate using conventional syphoning devices from the top-side of the substrate. Even without going to a double screened Jaubert Plenum System, Natural Nitrate Reduction does occur in systems utilizing capped tube UGF plates, provided the substrate is maintained at a 3 inch depth and deep burrowing animals are not abundant in the aquaria.
Using capped UGF plates in place of the egg-crate diffuser in your Jaubert Plenum enhances the capabilities of this type of System. When used in this manner, the UGF is not installed for the purpose of filtration, doing so would negate the purpose of the Jaubert Plenum. However, having the UGF in place, should you notice problem areas forming in the Jaubert Plenum, allows you to instantly alleviate the problem should it occur. Most aquarists who do use UGF plates in place of the egg-crate diffusers, cap off the lift tubes completely. I recommend leaving the caps off and placing a small strainer over the tubes. If an area of the substrate should begin to go anaerobic the hydrogen gas released from the area may, hopefully, rise through the lift tubes creating a draw in the plenum allowing oxygen to get to the area of concern, killing the anaerobes.
The Jaubert Plenum was designed to operate facilitatively aerobic/anaerobic, these bacteria commonly called nitrate respirators are semi-dormant in oxygen rich water and die with complete lack of oxygen. When anaerobic bacteria takes over, the risk to your aquarium is multiplied a thousand fold. Anaerobic bacteria can be any one of the bad guys, like e-colli, botulism, etc. it is almost impossible for you to pick which anaerobic bacteria will form in your aquarium, so it's best to keep the system operating with an emergency oxygenation source available, like a UGF.
Gary V. Deutschmann, Sr.