I have had a strong backlink for over 12 months now. However, BL was pointing to an unimportant inner site of my website. Therefore I changed the link and made it point on my home-site. Since then I had a significant drop in SERPs. Can always have other reasons of course, but it happened almost simultaneously. Therefore I believe there is a connection. I know that backlinks require some months to develop their full power. Do I start from zero now?