I use the blue water soluable pen, works great, the pencils always break on me too. And the purple one sometimes last till the next day and sometimes like you said only a few minutes! I have a white pen that I love for darks, they are kinda pricey, I think it was about 6 bucks , when you first make the mark it's invisible but shows up in a few seconds. Sometimes I use pencil but have heard that it doesn't always wash out.