Whats the best thing to use to make your nails grow strong?

I have already used nutra nail with green tea.Whats the best thing to use to make your nails grow strong?
biotin. it works really well and also helps your hair grow faster and stronger and your nails grow faster and stronger. my sister's been using it for years and she's really happy with it and tries to get me to use it but i always forget. she always has long strong nails when i see her. just go to a cvs or drug store or supermarket and look for it. its really great and trust me, you won't be disappointed.Whats the best thing to use to make your nails grow strong?
I have noticed since I have stopped taking my Calcium vitimans my nails won't grow past the tips of my fingers without breaking :(...I think it helped. I bought some Coral Calcium last night to see if that was what the problem is...
Do you take a multi-vitamin? I would recommend replacing that w/ a prenatal vitamin. (I use the Wal-Mart generic brand.)