Aquarium Water Filter Maintenance.
The next step after cleaning the glass will be washing the filter. Aquarium water continuously flows through the filter, so the aquarium and the filter form a single system, even if this filter is external relative to the aquarium. Thus, the accumulation of mechanical suspended solids in the filter does not mean that it is removed from the aquarium system. Invisible (dissolved in aquarium water) waste breakdown products can become harmful if allowed to accumulate and reach a concentration where they become toxic. In a biologically mature aquarium system, the nitrogen cycle and water changes protect fish from poisoning by the breakdown products of their own waste.
Solid residues of bacterial activity (sludge accumulating in the biological filter) are neutral and harmless. The presence of solid waste in the aquarium is not a disaster if the aquarium system is biologically “mature”. In a “mature” aquarium, as well as in the filter, waste is decomposed by nitrogen cycle bacteria. And invisible breakdown products pass through the filter. In addition to visible excrement, fish continuously release invisible but extremely toxic ammonia, so simply removing solid particles does not eliminate the need to process fish waste.
The filter maintenance schedule depends on the type of filtration—mechanical, chemical, or biological—as well as the type and model of the filter and the filter media used in it. Follow the filter manufacturers’ instructions in this regard.
Multi-compartment filters have several sections to accommodate various filter media and simultaneously perform mechanical, chemical, and biological water purification. At the same time, each of the filter media requires care at different times. A sponge or a bunch of synthetic threads will clog quickly and will probably need to be rinsed weekly, although eventually, they will still need to be replaced. Some filter materials (e.g., zeolite) can be regenerated, while some, most often chemical filter materials (e.g., peat or carbon), require regular replacement.
As for ceramics, one-third of it will need to be rinsed no more than once every six weeks, or even less often if possible. If the biological filtration media requires attention more frequently, it means that the volume of this material in the filter is likely insufficient for the given aquarium. In some cases, this simply indicates that the aquarium is overstocked with fish or that the fish are being overfed.
Mechanical filtration materials used only for trapping solid particles and having no biological action must be cleaned regularly. Dirt accumulates in these media, which the filter absorbs from the aquarium water. This should be done if the water flow in the filter has slowed down due to clogging. Biological filtration materials are best left untouched for as long as possible.
Any biological filter must be maintained in a way that returns it to operation as quickly as possible, since beneficial bacteria can die if deprived of oxygen-rich water flow for more than 2 hours. In a biological filter, only a portion of the filter media should be cleaned or replaced at a time. Usually, the maximum amount is one-third of the total filter media.
If the filter is cleaned completely or all filter media is replaced, the aquarium will be left without effective biological filtration for a long time. This will continue until the bacteria restore their population size in the cleaned environment or colonize a new one. As a result, high concentrations of ammonia and nitrites may occur in the aquarium, and the likelihood of fish poisoning will increase. If there are two or more biological filters in the aquarium, it is better to clean them in turns. Ammonia levels in the aquarium should be monitored daily for several days after biological filter maintenance.
In the most common internal filters, the filter medium consists of a special water-resistant foam. The filter is turned off, and carefully removed from the water (some filters provide the ability to disconnect the filter compartment without turning it off) and taken to the bathroom for washing. The filter medium should only be washed when necessary, i.e., when its overgrowth with bacterial films and sludge begins to hinder water pumping. Usually, it is enough to just rinse the sponge well under a stream of warm water, then insert it back into the filter and return it to the aquarium. Under no circumstances should any detergents be used. The purpose of this procedure is not to wash the sponge to sterile cleanliness, but to free the pores of the medium and restore a sufficiently free water flow through the filter.
However, about once every two months, it is useful to completely disassemble the filter mechanism, remove the rotor, and remove accumulated mucus and dirt from it, as well as clean the filter nozzle. An old, unnecessary toothbrush is very convenient for this purpose. Cleaning the filter media should consist solely of gently rinsing them in a bucket of aquarium water. Chlorine present in tap water kills bacteria. Water that is too hot also kills the beneficial bacteria inhabiting the filter medium. Any biological filter must be maintained in a way that returns it to operation as quickly as possible, since beneficial bacteria can die if deprived of oxygen-rich water flow for more than an hour.
If an undergravel filter is used, remove the air line from the air lift, as well as algae or scale deposits. Insert the siphon tube into the air lift of the undergravel filter and remove organic residues from under the plates. It is highly undesirable to clean the filter layer of the undergravel filter frequently – this will also lead to the death of a large number of beneficial bacteria.
Aeration Equipment Maintenance.
Piston air pumps (compressors) require regular lubrication and periodic maintenance. In both matters, follow the manufacturer’s instructions. Vibrator air pumps, and sometimes check valves, have air filters that require cleaning or replacement from time to time. Both of these devices may also have rubber diaphragms that lose their elasticity over time and must be replaced. New diaphragms can be purchased for air pumps, while check valves usually have to be replaced entirely.
Air tubing hoses eventually become hard, inflexible, and sometimes brittle – especially those parts that are submerged in water. If this problem occurs, replace or trim them. Clean the air line valve. Air stones often clog – sometimes due to bacteria, and in hard water, due to calcium carbonate deposits. In this case, they must be cleaned or replaced.
Lighting Equipment Maintenance.
Check the lighting equipment. Clean the reflector and aquarium hood with built-in lamps from dirt. Over time, the light output of fluorescent lamps decreases. Therefore, aquurists who grow plants in their aquariums prefer to replace them regularly – say, every six months – rather than waiting for them to stop working altogether.
If the lighting does not turn on, it does not always mean that the fluorescent lamp is faulty. The lamp ballast consists of two parts: the ballast choke and the starter. The latter looks like a small hermetically sealed cylinder entering the ballast so deeply that only its round end is visible. Starters cannot last forever, and without a working starter, when the ballast is turned on, the fluorescent lamp will not light up.
At the end of its lifespan, a fluorescent lamp usually flickers for a few days (or weeks) before going out completely. If it takes a long time for the lamp to light up after being turned on, or if it does not glow properly, the problem may be either in the lamp itself or in the starter. If a previously properly working lamp suddenly stops turning on, the problem is most likely the starter. A new starter of the required wattage can be purchased at electrical stores. The glass of the lamps should be periodically wiped clean of accumulated dirt.
Establishing and Maintaining Biological Balance in an Aquarium.
Checking Equipment Operability. Equipment and Tools for the Aquarium. 
