bet you have your pics posted on the main site album not the forum album and there is no link from here too it post them in the one when you click your name from this page. From the sounds of things and what i was going to tell you because i have had similar sounding problems (cant see pics) is you probably need Nitro but looks like you figured that out. If the lower leaves are the ones turning yellow from the bottom up and outside in then its probably nitro.

peace