Mario,
Your tree sounds like it is in stress, there are many other variables other than food i would suggest checking out first. Water and drainage off the top of my head can make citrus finicky. Lets start there.
SBL,
Now this is where people like ...
Moderator: OrganicBananac, I don't think that insulting any member here is the right course of action. Therefore I deleted the second part of the post and kept only the advice you see above.
Also, please note that we are here to exchange the knowledge, not trying to point out what others presumably don't know and harass them.
Please, read the rules once again and this time more carefully - here. Especially #1 and #3.