Just remembered you're using Alphatrak. The "take action" number on that is 68, instead of 50. Here's a guide for Alphatrak numbers, the same re-feeding etc would still apply, numbers are just slightly different.
When using an Alphatrak, I prefer to start the MC food if the BG is below 80-90 mg/dL early in the cycle. If the LC food doesn't bring the number up above 80 at the next retest in 20 minutes, then you want to feed the MC food and to retest again in 20 minutes.
WHEN that low happens is important. If you got that 80-90 later in the cycle, around +5 to +6, maybe a teaspoon of LC food would have done the trick.
If you got a number below 68 at mid-cycle, maybe a teaspoon of MC food would have been enough.
Early in the cycle, below 68, still dropping, bring out the HC food and have the simple sugar (karo, honey, corn syrup, etc.) standing by.