I bought a small (cheap) internal filter with a spray bar to maintain a 60L dennerle nano cube. However, the spray bar it came with constantly got clogged so I swapped it out with a botched DIY job dennerle eckfilter spray bar from their XL filter. It was a pain to do as my Dremel constantly overheats from its age but that's another story. The outcome IMO looks ok, there is some leaking from certain joints but I've found that to be useful as it creates bubbles to oxygenate the water somewhat. Some other opinions would be helpful on the results and whether it causes enough surface agitation thanks.