CHIRONOMIDS: Preferably, Bead head.
Take a string out with a big weight on the end, but mark the string in feet, this is to get the depth (unless you have sonar).
Now, take straight mono or Fluorocarbon...probably at least 6 lb.
Make a leader the length of the depth ( I do this up to 30')
Attach this straight to your floating line.
Now attach a Chironomid right on the end, then make a small 12' tag about 3 to 4' up from the bottom and attach another Chironomid.
Maybe put one "BB" size split shot about 6" up from the bottom one so it drops fast. Oh yeah if it is over 10' a slip indicator is a must.
Set the indicator so the bottom fly is suspended about a foot off the bottom.

Nice thing is, you are covering two different depths at a time. Adjust the bottom one accordingly, but I am betting with this heat, they are on the bottom.

Chironomids, maybe a black/white and a red one, but there are a bunch of colors to choose from.