Use "the" instead of "a" because it is first person. Unless, you wish to make the character who is talking seem mysterous when talking then use "A". Correction that should be made: I spent a few hours in the pool.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
clee62But to the reader, they don't know, should I use "a" instead?Ah! That's a really good question! You are touching on certain literary techniques for telling stories. I'm assuming that your sentence occurs in your text at a point where the/a pool has not been mentioned yet.