Wings, just an observation, watch your parameters after removing the bioballs, have observed that the removal of carbon that was left for over 3 months in 2 seperate tanks here resulted in a mini-cycle as the carbon had become a bacteria colony in the interim. Changing the balance caused both systems to 'wobble' while new bacteria established to fill the gap left by the removal of the bacteria. I'm sure that it will be the same with the bioballs, especially if you had a lot of them. Some time ago someone here was also removing his and was advised to do it in stages- seemed like good advice to me at the time...
Oh, heres your cookie....(lemon cream)