I think you can take out the hydro sponges. The 100 is a powerful filter and rated for a 110 gal. tank, double what your tank is. The flow rate for the 110 with media I think is 450 gph, so you are turning over the water in a 55 gal. tank at the rate of a 8 times per hour. I used my AC 500 (now the 110) on my 45 gal. tank well, always, and had crystal clear water, always, and never a problem with the bio filter, either.
Edit: Actually, Marie, if you remove them, I'd take one out at a time, wait maybe a month between removal to allow the AC media to catch up. Some people like Tina do have trouble with ACs restarting, I never did, but mine is from another era! 16 years old now. If yours have no trouble restarting then I don't think you have anything to worry about.