Aquarium Facility

The system, owned and operated by the University of California, extends from the end of the SIO pier to the SWFSC property line and consists of pumps, a flume on the SIO pier, sand and gravel filter beds, storage tanks, and piping.

The experimental aquarium occupies the entire basement in one of the four buildings which constitute the SWFSC. Fixed spaces supplied with running sea-water in this area include four completely enclosed and isolated environmental rooms, a small food-preparation room, and an office occupied by the resident aquarium manager. The remaining area is essentially a large room with no fixed walls, permitting tank sizes, types, and locations to be changed at will. All utility pipes and conduits are exposed and hung from the ceilings. The pipes carry sea-water, gas, and compressed air; the conduits carry 120-v and 205-v electricity. Large fluorescent lighting, rigged to a central timer, are hung throughout the aquarium. Ceiling height is 12 ft. between supporting beams and 10 ft. at the bottom of the beams. The floor is sealed concrete, sloped and crowned to drain water into gutters that run north and south for 100 ft. The gutters are 10 ft. away from the walls to prevent salt-water contact with the building's foundations.


The sea-water intake is at the end of the SIO pier, 900 ft. offshore, 7 ft. above the seabed and 13 ft. below the lowest tide level. Pacific Ocean water temperatures off the pier range from about 57 F(14 C) in winter to a maximum of 70 F(21 C) in summer. Salinity normally is from 33.55 to 33.70 parts per thousand.

Three suction pumps with stainless steel impellers bring sea-water into the delivery system. One pump is used while the other two are serviced or on standby. Normally the pumps are interchanged on a weekly basis. Sea-water is pumped from the ocean into a covered PVC flume, 15 by 15 inches, that extends the length of the pier. At this point, the raw sea-water enters a system of filter beds, storage tanks, transport pipes and reservoir, culminating in delivery of water to the basement sea-water aquarium at the SWFSC. Water brought in by the flume empties at about 600 gallons per minute into the top of two 10- by 20-ft. concrete filter beds. Each filter bed contains 12 inches of No. 12 crystal sand at the top, succeeded by 8 inches of pea gravel and 18 inches of rock laid across wooden battens with ½ -inch gaps so that the sea-water can drop into a pump pit. From the pump pit, 2 pumps move the filtered sea-water through dual 6-inch epoxy-lined transit pipes to three 60,000 gallon, concrete holding tanks 90 ft. above the filter bed.

Dual piping is used throughout the delivery system after it leaves the filter beds. The pipes are epoxy-lined cement whose smooth, glasslike lining permits easy cleaning. Delivery is alternated at weekly intervals from one pipe to the other; any settled organisms in the drained pipe dessicate and die. When water once again is delivered through the dry pipe, the first flush is usually sufficient to break away dead animals. The system also permits emergency repairs to be made without stopping the sea-water delivery.

Two large pumps at the 3 storage tanks push sea-water uphill for a distance of about one-half mile through 6-inch underground pipes to two additional 30,000-gallon, newly constructed, holding tanks. These large, new holding tanks not only supply the SWFSC aquarium, but the Stephen Birch aquariumThe previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries disclaimer as well as other small, SIO research facilitiesThe previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries disclaimer.

From these two holding tanks, the sea-water gravity feeds to a dual concrete reservoir of two 15,000-gallon tanks which directly supplies the SWFSC aquarium. Access openings and cleanouts are located at intervals along the path of the pipeline to facilitate cleaning and repair. At the reservoir, the sea-water cascades through a splash tower before going into one of the tanks. This tower is an 8- by 8- by 5-ft. structure of redwood siding with stepped wooden baffles that help to dissipate the excess air in the sea-water through mechanical action. Each of the concrete tanks is a self-contained unit, so that either one may be cleaned without interrupting the flow of water to the aquarium. Sea-water is heated about 2 C as it travels uphill to the SWFSC. This slight heating supersaturates the water with oxygen and nitrogen. Gas embolism killed some fish during early experiments and the splash tower has alleviated this problem.

The filtered sea-water enters the SWFSC through one or the other of two 6-inch PVC pipes. Because the reservoir tanks are 50 ft. above the level of the aquarium, the sea-water flows to the boilerroom by gravity feed at 50 p.s.i. At this point, the two 6-inch lines are valved so that each may be isolated for cleaning; they then enter a UV (ultraviolet light sterilizing) unit.

The UV unit (Aquafine Sterilizer model CSL-24R) is capable of disinfecting a maximum of 200 gallons per minute at greater than 99% efficiency.

Upon exiting the UV unit, the line is then divided into three 4-inch PVC lines. One of these lines carries ambient temperature sea-water and drops one floor level directly into the aquarium in the basement, another leads to a heating unit heat exchanger, and a third to a cooling unit heat exchanger. Thus, sea-water temperatures available in the aquarium range from about 4 C to greater than 30 C depending on current research requirements.

The vast majority of the aquariums' open floor space is currently devoted to 15 large, fiberglass tanks, ranging in size (100 - 2500 gal.) and shape (round, oval, rectangular). Various other smaller tanks are stored and available for specific needs.

Last modified: 12/24/2014