Up for sale is a nearly new Red Sea RSK-300 Protein Skimmer. It was used in my Reefer 170 for about a month. Love the skimmer, but over sized for my needs and went with a smaller skimmer for more refugium space. It is squeaky clean and ready to go, original box included! I also made a separate air tube with a valve for minor tuning of the air intake that I'll include. I'd prefer local pickup in Jacksonville, FL, but could arrange shipping if needed.