Any of them will work period as long as they are used in right amound and taken care of (meaning dont get crud built up on them) Bio balls seem to be older technology this day but work fine, A friend of mine really likes his pot scrubbies, I do not, He did just started using some ceramic rings and likes them. I use to have bio balls in my system but removed them because I was putting in the reactor (flud bed), After removing about 35 gallons of sumbmerged and drip plated bio balls the 8 liters of pond matrix was able to take over after they were removed and I saw no water spikes, so It really makes me wonder if the bio balls were really doing anything much. Pond matrix is kinda like ceramic rings that would be my choice. Real key to a ray it feed a large amount but not crazy too much and lots and lots of fresh water and allot of mechanical filtration to keep the tank clean. At least that is my input.