The Size of an Aquarium Surge Tank

Water movement is a critical factor for success with a reef aquarium. Small polyp stony corals in particular require strong current, even in the confines of an aquarium. Although aquarium dealers stock various types of powerheads and submersible pumps, these are not always sufficient to create optimal water movement. Surge tanks create a natural current.

  1. Identification

    • A surge tank is a container positioned above an aquarium. Water, either from the main aquarium or from the sump, a reservoir beneath the aquarium, is typically pumped up to fill the surge tank. Once full, this tank discharges its water into the aquarium in one powerful movement. Natural water movement is created through this process.

    Basic Dimensions

    • A 5-gallon bucket is an appropriate size for a surge tank. The pipe that feeds this surge tank should have a diameter of at least 0.5 inches. Place a lid on the surge tank to prevent water from splashing out and to stop dust and dirt from falling into it. A tightly fitting lid will also reduce noises from within surge tank. As a safety precaution, an overflow pipe should be installed in the surge tank. This overflow pipe is positioned to drain back into the main aquarium, should it ever need to drain excess water from the surge tank.

    Volumes

    • When a sump is being used, the submersible pump draws water from this reservoir and pushes it into the surge tank. The sump must hold sufficient water to accommodate this drop in level, without the pump running dry. The height of the main aquarium above the water level needs to be sufficient to accept the volume of water from the surge tank above it and to hold this water as it drains via pipes into the sump. The overflow drain from the aquarium to the sump must be of a sufficiently large diameter to drain the water quickly.

    Operation

    • The surge tank will add a great deal of bubbles to an aquarium, which will create conditions to which marine invertebrate animals, such as corals and anemones, are accustomed. The velocity of the water draining from a 5-gallon surge tank positioned 2 feet above the main aquarium and fed by a 0.5-inch pipe is approximately 4 feet per second.