Water sprite is a floating plant and will not grow well by planting its roots in gravels

We’ve been taught that germs are bad, that they cause disease and are something to fear. But that’s not entirely true. In the aquarium, some microorganisms are pathogenic, most are harmless, some examples of helpful microorganisms are the nitrifying bacteria.

Useful bacteria's help to break down the ammonia our fish excrete as waste in a process known as bio-filtration. Without these helpful bacteria, ammonia in the aquarium would quickly accumulate to lethal levels for the survival of fishes.

Another thing we were taught is that being clean is good and keeping an aquarium clean of waste is important, but we do not want to create too clean an environment that destroy those essential nitrifying bacteria. Therefore, we want our aquariums to be clean but not too clean.

Gravel Vacuum Cleaners are designed to separate and remove debris from the aquarium. As the water flows rapidly out of the hose end, it lift and tumble the gravel at its end and causing the dirt to rise and gravels to fall.

Start at the Bottom. The biggest deposit of helpful bacteria in our aquarium occurs on the surface of each gravel. Each grain, though appearing smooth to the eye, is rough at a microscopic level, therefore, provides a surface area for the growth of helpful bacteria.

Not knowing this, hobbyists sometimes remove the gravel for cleaning and have been known to boil it or worst of all, use bleach or soap to sterilize the gravel and kills off the nitrifying bacteria thereby will allow ammonia levels to increase rapidly in the water. Gravel should never be cleaned with anything but plain tap cool water.

The best way to clean gravel is with a gravel vacuum. This is a siphon hose with a large tube at one end. While siphoning out old water for partial water changes, the water flowing through the hose is strong enough to move and tumble the gravel at the same time suck-up the agitated solid waste.

The heavier gravel falls back to the tank bottom, while the dirt-laden water flows out the tube into a bucket for disposal. It’s quick and easy, and the helpful bacteria will remain intact on the gravel. You have to change water to dilute dissolved waste, anyway, so it’s a way to dispose of solid and dissolved waste in one quick process.

Remember to make the new water safe for both fish and helpful bacteria. Chlorine and chloramines are chemicals added by water treatment plants to kill germs.

If your tap water contains chlorine or chloramines... you must treat the new water with a tap water conditioner to neutralize them, so they do not destroy nitrifying bacteria or damage the mucous membranes of the fish.

Safely Maintaining Filters - The most significant part of your aquarium maintenance is likely to involve the cleaning of one or more filters. Filters don’t remove waste — they just collect it. Nitrifying bacteria grow on every solid surface in the tank, including gravel, glass, plants, decorations and filter media.

Most filters contain some type of bio-media designed to provide plenty of surface area for the growth of helpful bacteria. So, it’s best to take steps to preserve the bacteria on this media when possible.

Disposable Filter Media - Many filters use disposable media as a convenient way to clean the filter. When the media is dirty, you throw it away and replace it. Slide-in filter cartridges for power filters are the most common example.

But every time you replace disposable filter media, you throw out the good bacteria living on it. This may or may not be a problem. It depends on how much bio-filtration there is elsewhere in the tank.

For example, in a heavily planted aquarium with a gravel bed, it is unlikely to be a problem; there will be plenty of nitrifying bacteria colonizing those other sites. It would be different in a bare aquarium set up for hobbyists viewing enjoyment--the filter media would be the main source of bio-filtration in such a setup.

There are steps to play it safe. If your filter uses more than one filter cartridge, change them at alternate cleanings. This allows a seasoned filter cartridge to remain, while the new one colonizes with helpful bacteria.

Another option is to change the polyester filter media one time and the activated carbon the next--this will allow some seasoned media to remain in the tank while bacteria colonize the new media. Also, don’t replace media too often. If the polyester clogs in two weeks, it’s all right to rinse the solid waste off the filter cartridge and continue to use it for a couple more weeks.

Permanent Filter Media - The best filter designs incorporate some permanent media that you rinse and reuse instead of replacing it. So, you maintain the helpful bacteria living on the media. Examples include various sponges, ceramic noodles and the rotating bio-wheels found in some filters. Rinse these items to remove accumulated detritus, and they are ready to keep working.

When rinsing, take care not to harm helpful bacteria. Don’t sterilize the media or let it dry out, and do not use soap or hot water. Some hobbyists prefer old tank water for rinsing rather than risking having the chlorine in their tap water do damage. I would not leave media to soak in chlorinated tap water, because long exposure would destroy the helpful bacteria.

A good tip for maintaining helpful bacteria is to not turn the filter off, except for maintenance, especially with a canister filter. Helpful bacteria require oxygen. If a dirty canister is turned off, the helpful bacteria will use up the oxygen and die.

Because the filter is closed off from air, nitrifying bacteria will be replaced by anaerobic denitrifying bacteria, which do not need oxygen to break down waste.

These produce hydrogen sulfide and other toxic substances as a by-product. If you turn this dirty filter back on after having it off for a few hours, a day or a week, it may force poison into your tank. If you have a power outage, it’s a good idea to clean your canister filter before restarting it.