I would add a second blue filter pad above the bio-balls and replace one every 2 months or so. Do you have the Pro Clear wet/dry? I have always rinsed the pads with tap water twice a week, easier to clean thoroughly. I have never had a spike at all and nitrates are almost always at 0. I have found with the bio-balls and live rock, you have 100 lbs correct, you shouldn't have any problem. The 2 pads would be a benefit, with less detritus collecting on the bio-balls. Mine have no build up at all after 9 months. If you do eventually have build up, definitely rinse those off in tank water and about 1/3 at a time.