@40B Knasty We have one on the way to test out ourselves and I can provide you a more thorough answer thereafter. I imagine you could remove the filter cartridges completely and replace with a cut piece of Marine Pure along with filter floss and maybe even modify the cartridges. I will have to double check on the green sponge as well but it is likely just a bubble trap to ensure micro-bubbles are not a problem. Unfortunately, not too much information is available online at the moment but once we have the unit here for review, I will ensure we update the description and will be happy to answer your questions.
Until then, take care and happy reefkeeping!
-Robert @ MD