Just a quick question on what most people prefer to use. I've read that the idea is they have the near same surface area, however, everyone rants about how cheap scrubbies are and I can't find them cheap! Cost me around $15 for 18 of the scrubbies at walmart, and it seems that most dollar stores around here don't carry them for some weird reason. I looked on drs. foster and smith and found a gallon of bio balls for 7$, or a 5 gallon bucket for 28$. In this case, wouldn't bio balls prove to be more efficient and cost effective? Just looking for opinions, thanks!