- Makes perfect filtered DI aquarium water.

When setting up your freshwater aquarium filter, be sure to follow these 3 basic steps:-
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Undergravel filters – These filters are placed under a layer of gravel at the bottom of the tank. These freshwater aquarium filters rely on an air pump or powerhead to work. They are generally work well as biological filters, although many models include replaceable filters at the end of the tube for chemical or mechanical filtration
Do you think they deserve to be labeled as the Best Freshwater Aquarium Filter System?
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The Aqua Clear is better than most HOBs for biological filtration (if not the best) and is deservably very popular for this reason among many experienced aquarists.
However its flow design and filter media type tends to lead to flow-by, resulting in poor mechanical filtration especially for more fine debris/organic mulm.
For those doubting this, I performed tests using a “light” compost in the water and the Aqua Clear faired worse than all others tested. Figure 1.1APEX AQ-4020 Aquarium Water Filter
Photo provided by FlickrFigure 1.2APEX AQ-4020 Aquarium Water Filter
Photo provided by FlickrFigure 1.3APEX AQ-4050 Aquarium Water Filter
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Activated carbon for the aquarium is a form of carbon that is usually made from bituminous coal, lignite or wood. It is often abbreviated as AC on the forum. The primary use of activated carbon, or AC, is to filter the aquarium water of foul odors, yellowing compounds (DOC) and to remove medications from the water column. Some hobbyists use it regularly and some don't use it at all. Some swear at it and some swear by it. I'll try to give you the basic info to get you started and you can decide for yourself whether or not you think it's something you will want to use.The length of time that the reef’s biological filter takes to establish will vary from tank to tank. If the live rock or sand has just come from the ocean, then it is referred to as uncured. There are many organisms on the rock (sponges, tunicates, crabs, etc.) that will die off as a result of shipping. Therefore the rock needs to be placed into a vat or fishless aquarium to “cure.” Through the use of filtration and water changes, the die off ends and all of the forms of life, including bacteria, start to grow.Activated carbon comes in various shapes and sizes and not all activated carbon is equal. The most common shapes are granules and pellets. There are powder forms as well, but those are not used in aquariums. Generally speaking, the more porous and lighter the carbon the more surface area it has for adsorption thereby making it more effective at filtering the water. Many tap water filters are made to use activated carbon and it does a great job at removing odors from the water. This can apply to your aquarium as well.The main benefit of canister filtration is that the filter itself is virtually invisible, since the bulk of it resides beneath the aquarium, in the stand. Additionally, the powerful water movement and exceptionally large space for filtration media allows these filters to be used on large tanks or small tanks with large bio-loads. With quick disconnecting hoses, it is even easy to perform maintenance by taking the filter to the sink, so there is little mess and no spilled water.Canister filters are also external power filters, but generally sit under the aquarium due to their size and weight. They push or pull water through a set of media outside the tank in the filter housing. Canisters are a little different, though, in that they filter the water in a completely sealed, pressurized container. Water is again pulled into the unit through an uptake tube and passes through various media before being expelled to the aquarium again. Canister filters employ powerful pumps to move the water, so the flow rates are often in excess of what might be found in an external hang on power filter.Despite the advantage of maximal filtration in minimal size, trickle filters do take up some space, requiring that they typically be located underneath the tank, in the stand, like a canister filter. However, because the system is not sealed and under pressure like a canister, a means of transporting the water to and from the filter is needed. Overflows are the choice of getting water to the filter. These consist of a standpipe in the aquarium or a box suspended inside the tank with a strainer and a box outside the tank connected via a hose to the filter. Water then arrives at the filter, called a sump, where it passes through the pre-filter and into the trickle chamber. After this, the water proceeds to a last chamber containing a water pump to push the water back up a hose out of the sump and into the tank.