I for one had the same question when i returned to the hobby. After alot of reading, it seems that most people have moved away from bio balls. The thing that everyone is doing now is a media reactor with some type of nitrate/phosphate exporter (you also need a good skimmer). For example i use ecobak and many other on here do the same.
If you have your heart set on using Bioballs, remember that surface area is key, the more you have the more of the beneficial bacteria can grow that help the process. I have read the LR is better at this process then bioballs, but after time the live rock can become blocked and the efficiency goes way down. But again this is only what i have read so i could be incorrect.