Sold a complete HOB Skimmer to someone, even went to his house to set it up. I had Modified it to make it work better and had installed a Sponge on the Outlet to eliminate the micro bubbles. It was cleaned with Citric Acid, and looked new. Complained about the Micro Bubble, told him he needed to squeeze the sponge, and let it condition itself. Didn’t hear anything else. Eight months later, wants a full refund. There was a different aquarium in the background. He brought the Skimmer to my house, pump and parts are missing. Came close to calling the cops.