Floating test day 18

I agree with you that it can be hard to see much in an incubated egg at day 18, I am not sure that I think water testing them is always a good idea.
I am concerned with the potential of drowning your chick if they had piped internally earlier than expected. I think it would have been a good idea for you to at least mention this possibility, so that people could be informed/warned and be better able to make an informed decision about what they want to do. Depending on how familiar the person is with incubating, they may have had fluctuations in temps which could result in the eggs developing a bit quicker than expected.
I also think a video would maker it clearer/easier to understand for people not familiar with float testing incubated eggs.

Adding some pictures, a video and more details would make the article better