what do you put in a christmas tree water

I usually use water, but I've heard that you can also use sugar water or apple cider vinegar. You can also add a few drops of essential oils to make the tree smell nice. I've also heard of people adding a few drops of bleach to the water to prevent algae growth, but I don't recommend that. Bleach can be toxic if ingested, so it's best to keep it away from children and pets.