Tom,

Part of this problem may be the lack of sulfite in the PQ formulation. Sulfite is necessary to the superadditivity beteen the P and the Q. A very small amount will sufice, but some is necessary. I appears that the formation of hydroquinone monosulfonate is a necessary step in that synergism. OTH, the PC formula does not need sulfite for synergism.

I have not tried 1:1:200 with either one, but I'd be willing to bet that the PQ-Glycol would look more like the PC-Glycol if you added a gram or so of sulfite to the working solution.