The NFPA 70E Standard details multiple levels of Hazard Risk Categories (HRC) [see table 1.1], also called Levels. The greater the risk: the higher the HRC. Arc Rating is the factor that indicates which HRC is necessary, and can be measured in either ATPV or EBT.
The optimal pH range for brook trout appears to be 6.5-8.0,with a tolerance range of 4.0-9.5.Brook trout occur in waters with a wide range of alkalinity and specificconductance, although high alkalinity and high specific conductance usuallyincrease brook trout production (Cooper and Scherer 1967).
this preferred range differs slightly for each species temperatures between 50 and 65 degrees are prime for brown and rainbow trout brook trout and cutthroat trout evolved in slightly colder conditions so they prefer slightly colder watertemperatures between 60 and 63 degrees are optimum for most troutoxygen metabolism and the food chain dry fly requires a trout to rise to the surface this is one of the most energy intensive means of feeding for a trout trout in cold water are sluggish so your best bet for catching one is usually to drift a tiny nymph almost directly into its mouth