I have had my nano cube 24(31# Figi LR, 3-4 DSB) cycling for about a month and plan on taking things really slow and adding cleanup crew in 1-2 months--I have read numerous threads regarding the back chambers in my nano--I took out the sponges on Sun. and put in approx 2#'s LR rubble in each chamber(with carbon bag in chamber 2 as well)--I know it's not a perfect science and eveybody has a different opinion, but what's your take for the chambers--LR, LR rubble, or keep the sponges? Since I took the sponges out the water has been cloudy and am waiting for it to clear up--looking for some opinions--thanks,Deron