filter sock vs bio balls

[FF Rainwater]

fixing to redo the filtration on my tank, now it has bio balls but im thinking of doing away with them and puttting a filter sock there then my skimmer where the bio balls were in the first part of the sump...can i do that then just put live rock in the resevoir whre the return pump is? how should i set this thing up??

[jadams7]

Pictures of your sump always help, but yes putting a filter sock in there instead of bio balls sounds like a good idea to me. Unless properly maintained bio balls can have as many down sides as they do positives.