06-29-2016, 10:07 AM
This is usually a big drop in rankings, that happens over-night. If you notice that your site drops more than 10-20 positions on a multitude of keywords, this could indicate a penalty. A big difference between algorithmic and manual penalties is that the first ones are automatic and are usually released with various Google Updates, while the second ones are manually applied by a Google employee. Given the fact that Google made a habit out of making updates without clearly stating it, you should constantly monitor for ranking changes.