Originally Posted by brandielissa
yes they are so u think it would be pointless to have e xtra filtration?? also i have seen mention on here about filter current is this bad and how do i stop it?? I also have a bubble wall does this cause A current?? sorry for all the questions I am new to all this :)
Filtration is a complex issue at first, and I will be honest in saying that you will find differing points of view from several of us on this forum (and elsewhere) with respect to "how much" is good or bad. Very generally, the more fish or the larger the fish in an aquarium, the more important is the filtration because many fish or larger fish produce more waste and have a greater impact on what we term the bioload. Put simply, the bioload is the effect fish and invertebrates have on the biological state of the aquarium. A healthy and successful aquarium has a good biological equilibrium, meaning that the fish, plants, bacteria, and invertebrates are in balance. Filtration and cycling are related but are two very different things.
Fish produce ammonia constantly through respiration, and ammonia also occurs naturally from their waste and any biological decomposition (dead plant leaves, dead fish, uneaten fish food left in the tank, etc.). Ammonia is highly toxic to fish but there is a bacteria called nitrosomonas that "feeds" on ammonia and converts it to nitrite. Nitrite is also toxic, but another bacteria called nitrospira (nitrobacter sometimes) feeds on it and converts it to nitrate, which is relatively harmless in normal amounts. Nitrate is removed/diluted through the weekly partial water change.
It takes 5-8 days for nitrosomonas bacteria to establish themselves in a new tank, and once they do and begin producing nitrite the nitrospira bacteria take another 4-7 days (approx) to establish. During this period the fish in the tank are exposed to toxic ammonia and then toxic nitrite (unless there are live plants). Bacteria establish themselves by "colonizing" all surfaces--tank walls, every particle in the gravel, wood, rocks, decorations, and the media in the filter. Until these bacteria are established in sufficient numbers to handle the ammonia, the filter is basically useless biologically. It does however perform mechanical filtration, which is the removal of particulate matter in the water by making the water pass through the pads and media in the filter.
The presence of plants has a profound effect on how much filtration you need because plants do a tremendous job of filtration themselves, better than any mechanical filter we could use; this is provided there are enough of them to balance the fish load. Speaking solely with respect to planted aquaria, the less filtration (using filter equipment) the better. To grow, plants require ammonium, and ammonium comes from the ammonia I mentioned above. In acidic water (pH below 7.0) ammonia basically changes into ammonium, and the plants use it to grow. In basic/alkaline water (pH above 7.0) ammonia remains ammonia and the plants are able to use it by converting it into ammonium first. It is now also believed that plants can use nitrite by converting it back into ammonium, and many think that plants do this much faster and more effectively than the bacteria.
Another aspect of filtration is chemical, whereby we put certain substances in the filter to act on the water passing through it. Carbon is a common substance, as it removes various substances from the water. In a planted tank, these added filter substances are often detrimental because they remove things from the water than the plants may require, which is sort of like working in opposition. In a planted tank, filters we add should, in my view, only move the water through the tank and the filter media slowly; the mechanical filter removes suspended particulate matter, and returns the "clear" water to the aquarium. The plants and bacteria do the filtration that makes the water "clean".
Briefly on current, it is obviously connected to the amount and type of filters, and the strength of the flow should be dependant upon the type of fish [some prefer strong currents, others do not, and their original habitat and behaviours is the clue to this] and if there are plants [less flow is preferable in a planted tank for several reasons I won't mention now]. Bubble wands and such are fine but not in a planted tank because they work to drive off carbon dioxide (CO2) which the plants must have to grow.
So, if you aren't totally lost yet, to answer your question on how many filters...it depends upon the tank size, the number of fish, how big they are, and whether or not there are plants. And don't be afraid to ask questions; we all had to learn these things at one time, and I know others share my view that we are pleased to offer suggestions from our research and practical experiences.