Hi, I have been working on the internal filter part few weeks and finally made it.
The same power head(sobo 1000wp) is used. With a sponge in the bottom then the old media as mechanical media then some pumice stone (to grow good bacteria on the stone) and above that another high density sponge (scrub)
The two sponges above and below will act as mechanical media and the old media and pumice stone for biological media.
Any suggestions. Thanks in advance