Personally I like for my structure to be anchored. However,you can further enhance your floating pallets by using laundry baskets. Put your bottles in the basket and add hair curlers to the mix. Attach the basket to the underside of pallets so that the bottles and curlers can't escape. The curlers will serve the same purpose as bio balls, except they are much cheaper. They are great for growing biocultures and minnows and other small fish love them. Most laundry baskets will allow them to swim in and out freely.
