138 



C. DALE SNOW 



COVER 



\ l I I I I } I > I I I I I I I 1 1 1 ! I fi 



PLASTIC TEE 



RUBBER STOPPER 



SCREW CLAMP FOR 

 REGULAT INO 



PLY 



WATER SUP 



"t"joint detail 



REMOVABLE PARTITION" 



r'DRAIN HOLE WITH 

 RUBBER STOPPER 

 AND GLASS STAND 

 PIPE 



Figure 1. — Marine aquarium of the Oregon Fish Commission, Newport, Oreg. 



in some water tanks is the lining of the 

 tank with a polyethylene sheet. This not 

 only discourages Teredos and Limnoria 

 but facilitates cleaning of the tank. 

 Cleaning merely involves removal of the 

 polyethylene which can be hosed off. Un- 

 fortunately, with the polyethylene liner 

 you must depend upon siphoning action 

 for your water supply. 



Equipment failure has been a minor 

 problem in our system. This is particu- 

 larly true where the. storage tank's capac- 

 ity is such that it w^ill supply water for 

 several hours. We try to keep a spare 

 motor and impeller for the pump on hand 

 at all times, as these are the two items 

 most likely to cause trouble. 



The selection of a pump for a salt-water 

 system depends much on the use to which 

 the water will be put. In our work the 1 - 

 inch Jabsco pump has proven highly satis- 

 factory, but for some work this would be 



inadequate, particularly in oyster or larvae 

 work. The brass liner in this pump can 

 cause trouble. For larval rearing or oys- 

 ter studies a pump with a glass liner and 

 impeller is far better. 



Toxicity of components within the salt- 

 water system is highly important when 

 you are working with larval forms or con- 

 dition studies. This toxicity can come 

 from a number of sources: (1) The liner 

 or impeller of the pump; (2) materials 

 used to treat the tanks and aquarium 

 trays; and (3) some plastics used for 

 pipes or tank liners. In general it is best 

 to avoid all metals within the system. 

 Plastics such as Portco piping, polyethyl- 

 ene, and some of the new marine resins 

 are nontoxic to most invertebrate larvae 

 and have proven satisfactory in most in- 

 stances. Cements with high lime contents 

 should be avoided unless the material has 

 been cured for several years in salt water. 



