Final thoughts...

After looking at the two sources that I found in the text, I find it very reasonably to think that the writers of the book could have made an edit of the account of the water turning blood red. I am in no way discounting that it actually happened, but I believe it was due to either a bacteria caused the by the divine Protagonist:"Yahweh" , or by algae somehow occurring in the waters in the Nile. I venture to say that if events like that have happened in recent times they could have happened in the days of the text I reference.  I believe the writers were making a smart decision to say it was blood because they were trying to explain an event that did occur, and all the writers  did was make sense of it to them in their current mindset. To expound on that lets look at the time period in which it was written. Could the writers actually come up with a scientific reason why the river in the Nile turned red? Certainly not modern science is far more advanced now than it was back in those times, but I do commend them for making a good story with a definite twist.