Penalty for silo site

Hi

I think I got penalty for couple of my silos. My landing pages and supporting pages key phrases went down from page 1 to last page of google results...

The best thing is I didnt even got any backling, all I did was adding lot of unique content to each silo. And not all phrases were penalized - only those with a lot of supporting pages per silo (about 80) with similar intarnal linking in it...

I think that the reason of my penalty are internal anchor text, that`s why I`m changing it now to look more natural...

Do You guys ever got penalty for internal linking ?

My index page was not penalized (there were just couple internal links to my silos). I`m testing now:

1. On First penalized silo - I will remove all internal links pointing to each other within the silo
2. On the second silo - I will remove my main word from all internal links - I will se what happens (it`s about 11% density of that word thanks to interal links...)
3. On third - I will make all internal links anchor text look nautral
4. I got about 300 sites per 5 silos so from now on - I will create about 20 silos and put there max. 20 pages per silo

And I will wait till my site will be recrawled, to see what`s working best