Marmalade - Update

When passing by my parents house the other day I noticed that their citrus trees were loaded with ripe fruit.  What does one do with an overabundance of grapefruit and oranges?  Give them to your daughter of course.  And what does the daughter do with them?  Marmalade!  I've made lots of different types of jams and jellies, but this was my first foray into the world of marmalade.  That night I made a batch of grapefruit marmalade.  I'm a little worried that it cooked too long.  Hopefully it sets properly, and if it does I'll post a recipe so that I can remember next season. 

UPDATE:  The marmalade set...boy did it ever set.  I'm pretty sure it could break a tooth (might have cooked it a wee bit past the gel stage).  EPIC FAIL!