sentences:  Filtered seawater from Monterey Bay is pumped into the Kelp Forest and other exhibits at per minute.At night, unfiltered seawater (or "raw seawater") is used for the Kelp Forest exhibit to maintain its realistic appearance.The use of unfiltered seawater allows animals to grow in the aquarium's plumbing so it must occasionally be cleaned with tools called pigs, which blast through the pipes under pressure to remove organisms and debris.