Layne Norton Peak Week: Water & Sodium
Here is a good article that talks about sodium depletion/intake and how it works in the body, also talks a bit about potassium intake and how aldosterone levels are affected. Aldosterone is the hormone responsible for re-absorption and retention of water and sodium.
In the article they also have a hyperlink connecting to an article about carb loading, worth checking out as well.
What's the macros of your diet right now? I saw above you're at 1800 cal which leads me to believe you're already on relatively low carbs. You could cut your carbs and sodium for a few days, allow your aldosterone levels to double up and then you could do a refeed the day prior with probably 1.5-2x the amount of carbs as your previous regular intake, but without having practiced or experience with exactly how your body is going to react it's difficult to know how much is the right amount. Probably better airing on the side of caution so you don't "spill over". Scan through that article though I think it offers some good information. Ultimately, every coach and competitor is going to have a different method for carb loading and sodium/water manipulation bc it all ends up working different for everyone, so it normally takes trying it a time or two to know the best protocol for your body.
Hope this helps, sorry I can't give more specific answers, I'm still few months out from my first competition so I haven't had the ability to try these things for myself, just read about it and talked to some coaches about it haha.