I don't know whether I received a bad bottle of Omas Blue last year. All I know is that I've owned two bottles of Omas Blue, and the second one was the worst gusher imaginable. It's misleading to call the two inks by the same name. Diluting it with Waterman Florida Blue fixed it. (WFB never looked better. But I digress.)
I tried a 2:1 mix, Omas over WFB, but that was pushing it. The flow was still too heavy: too much partial bleed-through with too many pens on too many papers. At 1:1, every pen/nib I owned could handle it.
If this seems strange, lucky you. It means you didn't buy this stuff, whatever it was. In any case, read on. (If the image colors on your monitor differ from my descriptions, heed my descriptions. Carry on.)