First thing cut the sponge in half lengthwise and then stack the two halves one on top the other in the filter. Same amount of sponge but alot easier to clean. I clean my sponges in hot tap water, always have. I rinse the biomax in tank water. I intend for the BB to colonate the biomax not the sponge. Have tested and never seen any sort of mini cycle while doing this.
Same here, except for the cutting in half trick(one day I'll remember to try that one)