I took my Giga Power (GST-100) stove out last night. I was actually able to get a pretty low flame.

I wonder if you got an oddball? What conditions are you using yours in? I was in about 90F weather with light wind (I was using a windscreen). I had not problem getting what I would call a simmering flame.

The only real problem I've had with the GST-100 is that it has such a small flame that my pot often gets a hot spot right under the flame. For real simmering, I prefer a wider burner head. But as for the flame adjustment itself, my GST-100 turns down pretty low and still maintains a stable flame.

HJ