I have a Aquaone CF1200
I run Eheim Subatrate Pro which is apparently Sintered Quartz, in the bottom 2 Trays
Then I have Carbon with Filter Wool in the Top Tray, I dont use carbon all the time, so when not using the Carbon, I just fill the Top Tray with Filter Wool.
Great wee Filters, I have 2 of these, 1 on my Discus Tank and 1 on my Community Tank.