An alternative to LR rubble is Seachem's MATRIX biomedia. It is a porous rock media that you can put in filter bags in place of the bioballs. Then it's easy to pull out the filter bag and shake off any detritus that may build up over time. The advantage of LR rubble or something like matrix is that you can get at least some level of nitrate reduction as well ammonia/nitrite reduction. With bioballs you'll never get any nitrate reduction no matter how clean you keep them.