I had a saltwater aquarium cycling for about 2 months and had a bad bristle worm problem. There were no fish in the tank so I decided to just scrap the live rock and sand, and start all over again. However, I’m wondering if I should replace the filter media or does it still obtain BB.
I’d scrap the filter media but in all honesty I’d suggest not worrying about bristle worms
Scrap the filter media if you are concerned. It's not like freshwater where you lose your cycle with throwing out the filter media/screen.