When the water is low & clear 6X couldn't hurt, but it probably wasn't the problem. My fishing on Sunday netted me 1/3 of the fish I caught on Wed, and Sunday I was on a better section. I guess that's why they call it fishing, and not catching
Sometimes those Brookies seem to stay in hiding. You also may be starting a bit too early.
Ooh and if you are just dry fly fishing, that could also be a problem. On Sunday EVERY fish I caught was on the dropper
. I see you were using nymphs. Were you high sticking, or using an indicator. I know when I high stick, I don't even notice many subtle strikes
You alsoneed to become a boot print detective. If you see boot prints I'd find a new section to fish.
My buddy blamed the full moon for the slow fishing Sunday. I'm sure others may chime in with other ideas