sump question ?

hello everyone. i currently have a 75g sump with a protein skimmer, a filter sock and lots of rock. my question is. do i need anything else in it ? a lot of ppl have more things in their sump to meet their needs. i know that "if its not broken don't fix it" but i want just wondering if there is anything that I'm missing, just for preventive care.



also, do i need to clean a sump ? just because there is a lot of junk on the rocks and at the bottom. (don't have a sand bed in my sump)



thank u for ur thoughts.