Kaix
07-27-2006, 02:29 PM
Biological Filters
Just how effective is this and what is it anyway? The most common Biological filter in use is the Undergravel Filter, or sometimes called Sub-sand filter. A porous filtering plate, usually made of plastic, is filled with sand or gravel to about 3" thick. Air bubbles lift water up the airlift tube. Water is forced by natural forces to flow through the gravel/sand, to the undergravel plate, under the filter plate and up to the uplift tube.
Commercially available powerheads can be adapted to fit on the up-lift tube, making it even more effective. For this filter to be most effective, the plate must cover at least 60% of the base. 100% is most ideal. With the gravel or sand acting as the filtering media, your whole tank becomes the filter. The gravel or sand is expected to be dirty over time. What happens here is that bacteria will grow in the gravel or sand and convert the ammonia & nitrites to nitrates (chemical filtration), which can then be removed by the live plants or by water changes. Large dirt particles will be trapped at the lowest point of the gravel and should be constantly removed via weekly/fortnightly or monthly partial water changes.
At least once, feed your fish with tubifex worms. Place a small bowl or dish in the tank and place cleaned worms in the dish. Spread a small lot all over the tank (Do NOT OVER DO THIS). The worms will go into the gravel and help keep the gravel from choking-up - just like earthworms in the garden soil. Should they manage to reach the plate, they will be pulled out through the airlift tube and become a nice treat for the fishes.
Important note: the gravel or sand must NOT be coral sand, crush corals, etc., unless your setup is Marine or for Hard Alkaline water fishes.
If you are using crushed corals, as water flows through the sand at a constant rate, it will dissolve part of the coral, and the water will become harder and harder over time. The pH will also increase along with it. For this reason, if you do not intend to change water regularly, DO NOT USE Crush Corals, Shell, or shell grit in your filtering tank. This is the most common problem in large Koi Pond set-up. Because the tank size is huge, water is hardly ever changed. Overtime, the water gets too hard and alkaline and the Kois or Goldfishes become stressed. Tell tale signs will be revealed later when I touch on Preventive Medicine.
After setting up an undergravel filter, your tank water MUST be crystal clear in 12 hours. If not, your filter is not working. Your pump may not be working properly.
Good gravel/pebble size is between 3-5mm. Take a sample of the gravel/sand, place in a glass container, pour vinegar or other forms of acid. If there is
strong reaction - effervescence - do not use for acidic fishes. Slight or no reaction. Its OKAY to use.
If you do not intend to use undergravel filter system, it is better not to use any sand/gravel at all.
Advantages of using an undergravel fiter:
Cheap & cost effective
Cannot be used if fish digs.
Needs 2 weeks for bacteria to grow.
Gravel type very important.
Can use just an air pump or pumphead.
Safe even if there are baby fishes.
Just how effective is this and what is it anyway? The most common Biological filter in use is the Undergravel Filter, or sometimes called Sub-sand filter. A porous filtering plate, usually made of plastic, is filled with sand or gravel to about 3" thick. Air bubbles lift water up the airlift tube. Water is forced by natural forces to flow through the gravel/sand, to the undergravel plate, under the filter plate and up to the uplift tube.
Commercially available powerheads can be adapted to fit on the up-lift tube, making it even more effective. For this filter to be most effective, the plate must cover at least 60% of the base. 100% is most ideal. With the gravel or sand acting as the filtering media, your whole tank becomes the filter. The gravel or sand is expected to be dirty over time. What happens here is that bacteria will grow in the gravel or sand and convert the ammonia & nitrites to nitrates (chemical filtration), which can then be removed by the live plants or by water changes. Large dirt particles will be trapped at the lowest point of the gravel and should be constantly removed via weekly/fortnightly or monthly partial water changes.
At least once, feed your fish with tubifex worms. Place a small bowl or dish in the tank and place cleaned worms in the dish. Spread a small lot all over the tank (Do NOT OVER DO THIS). The worms will go into the gravel and help keep the gravel from choking-up - just like earthworms in the garden soil. Should they manage to reach the plate, they will be pulled out through the airlift tube and become a nice treat for the fishes.
Important note: the gravel or sand must NOT be coral sand, crush corals, etc., unless your setup is Marine or for Hard Alkaline water fishes.
If you are using crushed corals, as water flows through the sand at a constant rate, it will dissolve part of the coral, and the water will become harder and harder over time. The pH will also increase along with it. For this reason, if you do not intend to change water regularly, DO NOT USE Crush Corals, Shell, or shell grit in your filtering tank. This is the most common problem in large Koi Pond set-up. Because the tank size is huge, water is hardly ever changed. Overtime, the water gets too hard and alkaline and the Kois or Goldfishes become stressed. Tell tale signs will be revealed later when I touch on Preventive Medicine.
After setting up an undergravel filter, your tank water MUST be crystal clear in 12 hours. If not, your filter is not working. Your pump may not be working properly.
Good gravel/pebble size is between 3-5mm. Take a sample of the gravel/sand, place in a glass container, pour vinegar or other forms of acid. If there is
strong reaction - effervescence - do not use for acidic fishes. Slight or no reaction. Its OKAY to use.
If you do not intend to use undergravel filter system, it is better not to use any sand/gravel at all.
Advantages of using an undergravel fiter:
Cheap & cost effective
Cannot be used if fish digs.
Needs 2 weeks for bacteria to grow.
Gravel type very important.
Can use just an air pump or pumphead.
Safe even if there are baby fishes.