I'm glad to hear the site's helping you find good trades! Originally I had the lookback period and refresh interval separate but I combined them for the sake of getting the site up asap. The problem arises when a duplicate entry is formed, ie. when a symbol is displayed and then on the next refresh it is also displayed again. What should happen in this case? I'm thinking that it should replace the original entry if it has dropped by MORE than was shown in the the original entry, otherwise the original entry should remain. But then at what point should it not be shown anymore? When the user marks it as seen? After a certain period of time?

Once I know what's preferred I can get started on implementing it :)