Providing you have the ceramic disc media running in the ac70 now,just take the sponge out of the ac70, knock off the really big chunks. Then squeeze the sponge into the 6 gal. Replace sponge back into ac70. Use as much media from existing 70 as you can in the new filter on back of the 6gal. Run some floss on top of whatever other media you grabbed from the 70 to help clear the detritus from the water column.Instantly cycled tank. In the meantyme run some floss in the back of the 70, so you can squeeze more good bacteria into the 6gal. in a couple more days after the initial tyme.