Glass Reef - The Basics - Overflow

Glass Reef - The Basics - Overflow: "This one shows the 1/4" tubing for the air inlet on the open channel standpipe. It's not visible in the pic, but the tubing ends about a 1/4" above the normal water level in the overflow box. Should, for whatever reason, the water level in the box rise, the open end of the tube becomes covered with water, which shuts off any air access to the standpipe. This causes the normally open channel standpipe to become a full syphon standpipe. At this point the volume of water that the pipe can handle rises. More water flows down the pipe, which causes the water level in the overflow box to sink. As soon as the water level falls below the end of the 1/4" tubing, air can enter the pipe and it reverts back to its open channel status. In this way the overflow design automatically adjusts itself to changing conditions."

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