The pace and manner in which Stillwater food sources move is a prime consideration. Stillwater food sources are not Olympic athletes capable of great speeds. For the most part they crawl, wiggle, or swim in a slow random fashion. Your sinking fly line must allow you to retrieve your pattern in a realistic manner without dragging it into the weeds and bottom debris. Water temperature also plays a role. Cooler water reduces a trout’s metabolism thereby reducing their activity. Retrieves must be slow to be successful. Unsettled weather also reduces trout activity dictating pedestrian retrieves coupled with slow sinking lines. RIO AquaLux Clear Intermediate or Hover lines are my preferred choices in these conditions. Active trout and attractor flies allow for brisk retrieves and faster sink rate lines
Knowing the sink rate of a line allows you to consistently count your line down to a specific depth. With a little math it is easy to place your fly at the same level on successive presentations. The rule of 12 is your key to this puzzle. Dividing the sink rate of your line into 12 determines how long it takes your fly line to sink one foot. Once you know how long it takes to sink a foot all you have to do is multiply this number by your target depth to know how long to let your line sink. For example, if you are anchored in 12 feet of water and there is roughly 1-2 feet of weeds growing along the bottom presenting your fly at 10 feet would be a good starting point. Trout tend to cruise near the bottom in and around the weed tops. A type III sinking line sinks at three inches per second. Using the rule of 12, three divided into 12 reveals that it will take your line four seconds to sink one foot. To reach 10 feet a type III line would need to sink 40 seconds (4 x 10=40). If you choose a type III sinking line you can begin exploring the water using a 40 second countdown. If you hang up you might have to reduce the sink time or increase your retrieve speed to avoid the weed tops. Adjusting your sink time in five second increments is a good starting point. If you are still hanging up more than you would like switching to a slower sink rate line would be the next option.