In Norwegian there is a phrase, piss i havet, that directly translated means; piss in the ocean. This phrase is used when talking about something that might usually be significant, but looked at in the bigger picture, it is insignificant. Now, this concept seems quite basic to me, so I believe that there is an English equivalent. I'll give some examples of where the phrase is used, to better paint a picture of what I mean.
Usually, dropping a hammer is an unpleasant and loud sound. It will garner attention and people will be affected by it. Perhaps they'll tell you to not drop the hammer so much. If you are on the middle of the hellfire of war, on the battlefield, dropping a hammer would not garner much attention. The noise it makes blends in as soft sound when there are much louder sounds about. The noise of the hammer dropping therefore becomes piss in the ocean. What is the actual phrase for this?
Another example is, if you're making an absurd million dollars every week, five dollars becomes piss in the ocean.