114 



WARREN WISBY 



of Biscayne Bay with the Atlantic Ocean. 

 Water conditions in Bear Cut vaiy from 

 relatively clear water free of suspended 

 materials, on an incoming tide, to rather 

 turbid water with a silicaceous silt load 

 on an outgoing tide. Turbidity increases 

 when winds are high and especially when 

 high winds are combined with spring tides. 



The intake for the present salt-water 

 system is fastened to the laboratoi-y pier 

 and consists of a screened foot valve, 

 which is easily removed for cleaning, 

 within a sturdy box which is itself fitted 

 with easily removable, coarse, stainless- 

 steel screening. The foot valve is located 

 about 6 feet under the surface of the water 

 at mean tide, placing it about the same 

 distance over the bottom. The intake 

 line, about 50 feet in length, is composed 

 of 3-inch black polyethylene pipe and 

 leads to a manifold which is connected to 

 the suction side of two Jaeger centrifugal 

 pumps, each of which is powered by a 

 3-phase, 1-horsepower motor. The pumps 

 have a rated capacity of 50 gallons per 

 minute under these operating conditions 

 and are so valved that either pump can 

 be placed in service. The initial cost of 

 these pumps is remarkably low, and it is 

 therefore feasible to keep standby units on 

 hand. Furthermore, repairs are not 

 costly and are, as a matter of fact, infre- 

 quent. This type of pump is commonly 

 used in construction work, and repair fa- 

 cilities should be available in most cities. 

 Repairs have usually consisted in re- 

 placement of worn impellers and an oc- 

 casional volute, neither of which requires 

 a large expenditure of funds or of time 

 since the pump can easily be loaded into 

 an automobile and taken to the repair 

 shop. 



The discharge line is also manifolded 

 at the pumps and is also composed of 3- 

 inch black polyethylene pipe, which has 

 been covered with aluminum paint so as 

 to reduce absorption of heat by the water. 



This line empties into one end of a con- 

 crete tank (lO-by-lO-by-2-feet) situated 

 on the roof of the building. Here the 

 flow is diffused over a maximum cross sec- 

 tion and rendered relatively nonturbulent, 

 by means of removable baffles, in order to 

 reduce the rate of linear flow so that most 

 of the settleable materials are removed. 

 The water level is maintained by means of 

 an electric float switch which controls that 

 pump which happens to be in service. 

 The tank is equipped with a hinged cover 

 to exclude sunlight and accompanying 

 algal growth, and a removable ovei*flow 

 drain which leads back to the bay. Re- 

 moval of the overflow standpipe allows 

 the settled materials to be flushed and the 

 tank to be cleaned. 



The secondary, or distribution, system 

 leaves through a screened outlet located a 

 few inches above the tank floor. It is con- 

 structed of the same kind of pipe as are 

 the suction and primary discharge lines. 

 Branches of this system travel down each 

 side of the building for final distribution 

 to the water tables and aquariums. In no 

 case does any pipe have a blind, capped 

 end. Rather, the end of each pipe is fitted 

 with a valve and a discharge line which 

 leads back to the bay, so that the accumu- 

 lation of sediment, with resultant forma- 

 tion of HoS, can be prevented by frequent 

 flushing of all parts of the system. The 

 same arrangement is provided in the 

 smaller lines which supply the individual 

 aquariums. Also it was found that sedi- 

 mentation ceased to be a factor in clog- 

 ging of valves, which are all of plastic 

 (PVC), if the lines which supplied the 

 aquariums, as well as the plastic stop- 

 cocks from these lines, were connected to 

 the upper side of the distribution line in- 

 stead of the bottom, as is usually the case. 



The water tables are constructed of 

 fiberglass-covered plywood, are standard- 

 ized as to size and design, and are easily 

 movable. Each has two levels which are 



