What is the black precipitate sediment showing up in the bottom of our Rhodium tank after about 3 weeks of use. We plate 200-300 pieces a day. We keep things extremely clean: ultrasonic, steam, electrocleaner, acid dip and keep our plating baths covered when not in use. They are also inside a Lab hood which is closed when we aren’t plating something. I don’t know that this sediment is causing any problems, but I am wondering if anyone else sees this and what it might be. I’ve been looking into filtering the bath, but absent actual problems don’t know that it’s necessary.