Potential media upgrades:
The white filter pad supplied with the tank will provide mechanical filtration and some biological filtration. However,
if this is completely replaced each time, the mature biological media is lost. However, there are various ways that the
media can be upgraded from that supplied.
Firstly, you can use foam instead, which can be rinsed (in water taken from the tank) and re-used, or add some
biological media below the white pad.
The foam/sponge can be cut to size from larger pieces (such as those available for pond filters).
You can also place biological media such as Eheim Substrat Pro below the pad, so that the water is first strained
mechanically by the white pad and then flows through the biomedia.