Just as a gardener pulls up weeds that would overgrow the flowers, undesirable weedy organisms and certain sponges and algae that could overgrow corals are periodically removed. Organisms that kill corals, such as the crown of thorns starfish and certain coral-eating snails are eliminated.
Biorock reefs also need to be periodically checked to ensure that cables and connections are intact. If these wires are broken, growth of mineral accretion will stop and growth rates of corals will decrease to normal values and lose their special ability to resist adverse conditions. If problems are found with a cable, it is repaired or replaced as needed.