I just got a new tank and it came with some large plastic resin decorations. They are coated in algae as this tank was very neglected and was the home to 6 koi (the koi are now very happy swimming in my pond). I would like to use the decorations as they are very nice but I have no idea what the best way to clean them would be. Can I soak them in a bleach solution if I rinse them really well afterward? How would you clean them? Thanks!