Kept the hose end under the fluid is the whole trick, that's what stops the air from sneaking back in. Take it a step further and crack the bleeder just a hair, then let gravity do the work for a minute before you even touch the pedal. Way less chance of foaming the fluid or pulling air past the threads.

Man, I ate my words on that one too. I always figured mag floats were for the old guys who wanted to baby their arms, and I stuck with wood for years because thats what I learned on. Then a buddy handed me his one day when my shoulders were already shot, and I swear I floated the rest of that pour with way less fight. The thing glides instead of dragging, so you are not muscling every pass. Took me about ten minutes to see I had been doing it the hard way the whole time. Still grab my wood float for some stuff, but I get it now.