Because of the cost, price, market and other reasons, most of the finished tanks are ordinary upper filtration, but a few are side filtration and reverse filtration. Of course, there is also a bottom filter. As shown in the figure:
The advantages of bottom filtration are strong filtration capacity, stable water quality and clean main cylinder. Therefore, it is the main filtering method for seawater tanks and large feng shui tanks at present.
In fact, the ordinary finished product tank can also be transformed into a bottom filter fish tank, which can be transformed into an overflow type with holes or a siphon type without holes.