One pound = 453.6 grams 



One gallon = 3,785 grams = 8.3 pounds 



One gallon = 128 fluid ounces = 8 pints 



One quart = 2 pints = 946 c.c. 



One pint = 473 c.c. = 0.550599 liters = 16 fluid ounces 



One part per million =8.3 pounds per million gallons of water 



One part per million = 1 milligram (mg.) per liter 



1 gram = 100 mg; one microgram = 0.000001 mg. = 0.001 p. p.m. 



CONTROL OF POND SCUMS AND OTHER ALGAE 



When yellowish-green or green scums form on the surfaces of 

 ponds, fishing in them becomes almost impossible. Examples of 

 scum-forming filamentous green algae are Hydrodictyon , Pithophora , 

 Cladophora , Oedogonium , Zygnema , Mougeotia and Spirogyra . The time 

 to control these growths is in the early stages of their development 

 when they first appear on the surface of the pond. Copper sulfate 

 is an effective agent for this, but sodium arsenite has been found 

 equally effective, or even more effective, on thick scums that 

 cover the entire water surface. Sodium arsenite treatments at 

 4.0 p. p.m., based on the entire volume of water in the pond, have 

 been used effectively, but spraying is confined mostly to the 

 surface scums. Copper sulfate treatments of hard-water ponds at 

 Leetown, West Virginia, were based on a rate of 1.0 part per million 

 (p. p.m.) or 8.3 pounds of copper sulfate (CuSo4 . 5H20) per one 

 million gallons of water in the pond. Half that quantity should 

 be used in soft water. Snow (1959) recommends 0.33 p. p.m. copper 

 sulfate applied daily for five days to control Hydrodictyon and 

 Pithophora , if treated in an early stage of development. 



When heavy algal growths in ponds are suddenly killed, serious 

 oxygen depletion may follow. Treatment of a section of a pond at 

 a time, or the turning (or pumping) into the pond of additional 

 fresh water at the proper time will prevent loss of fish. 



The early toxicity tests by Moore and Kellerman (1905) 

 indicated that sunfish could withstand concentrations up to 1.2 

 p. p.m., and bass up to 2.1 p. p.m. of copper sulfate in soft water. 

 The limits are apparently much higher in hard water. 



Recent (1959) toxicity tests, however, by John R. Anderson 

 (unpublished) _1/ conducted in aquaria at Marion, Alabama, showed 

 that two-inch bluegills begin to die at a concentration of 0.25 

 p. p.m., but that 100 per cent mortality did not occur until the 

 concentration of copper sulfate reached 0.8 p. p.m. in soft water 

 having a total hardness (TH) of 15 p. p.m. In contrast, water having 

 a total hardness of 132 p. p.m. and a total alkalinity of 1544 p. p.m. 

 did not kill bluegills until a 10 p. p.m. level was reached. Seventy 

 p. p.m. was required to obtain 100 per cent mortality. The 48-hour 



j^/ These results are quoted with the permission of John R. Anderson, 

 U. S. Fish and Wildlife Service, Fort Worth, Texas. 



