no, skin only darkens when exposed to UV rays, so when it is dark outside, and you are not exposed to the sun, your skin will thus not darken.
if you mean without tanning or false tanning, there is no other way to darken your skin
Yes Salt can dry out your skin...or at least Salt Water can like the Ocean
yes?
Hard water itself does not directly darken skin color. However, the minerals in hard water, such as calcium and magnesium, can lead to dryness and irritation, which may affect the skin's appearance. Over time, dry skin can appear dull or darker due to a lack of moisture and proper exfoliation. Additionally, any skin reactions or conditions caused by hard water could potentially lead to hyperpigmentation or discoloration.
No, it is not harmful.
UV rays transfer energy into the dead particles into your hair, lightening it, and since your skin isn't dead, it will darken it.
No
It is not recommended; after drying salt remain on the skin.
It's because the salt from the water stays on your skin, and the sun drys it out. So if you need to use lotion.
Your skin gets wet and salty
No. A sauna is (in simple terms) a steam bath. In order for your skin to darken, the melanin in your body needs to react with ultra-violet light.
Salt water is great for acne. You could cleanse your skin with salt water at the beach or you can make salt water at home. All you need to do is mix a few tablespoons of salt into your bath. (I'd prefer using sea salt.) The salt may sting a bit, but that's normal. When your done, moisturize a bit with lotion so you won't dry your skin. If you have sensitive skin, I recommend you don't try this technique.