402 FISH HAICHKRY MANAGEMENT 



Calculations for Prolonged-Bath Treatments 



The basic formula for computing the amount of chemical needed is: 



capacity final 



(volume) of concentration correction 



water to x desired x factor . , . 



, \ weight of 



be treated Ippmj , . , 



— = chemical 



strength of chemical (decimal) needed 



The units of measure and the correction factor (Table G-l) that correlates 

 volume with weight vary with the size of the unit to be treated. The chem- 

 ical strength is the fraction of a chemical preparation that is active in- 

 gredient when purchased; ppm is parts per million. 



For example, in smaller hatchery units, gallon capacities usually are 

 used. Chemicals typically are measured in grams because small amounts 

 are usually needed, and metric balances are more accurate than English 

 ones in this range. The correction factor is 0.0038 (grams/gallon). 



Examples: 



(1) How much Dylox (50"(i active ingredient) is needed for a 0.25 ppm 

 treatment of a 390-gallon tank? 



390x0.25x0.0038 ^ ^, 



= 0.74 erams Uyiox 



0.50 ^ ^ 



(2) How much copper sulfate (lOO'/o active ingredient) is needed for a 

 1:6,000 treatment of that 390-gallon tank? 



390x167x0.0038 ^,^ ^ ^^ 



=- 247 grams CuSO. 



1.00 ^ * 



Table G-1. correction factors used to convert volume or capacity to 



WEIGHT IN calculations OF CHEMICAL CONCENTRATION. 



Units Correction Factor 



grams (or milliliters)/gaIlon 0.00378 



grams (or milliliters)/cubic foot 0.02828 



grams (or milliliters)/cubic yard 0.76366 



ounces (fluid)/cubic foot 0.00096 



ounces (nuid)/cubic yard 0.0258.'i 



ounces (weight)/cubic foot 0.00100 



ounces (weight)/cubic yard 0.02694 



pounds/cubic foot 0.00006 



pounds/cubic yard 0.00168 



pounds/acre-foot 2.7181 



