I boiled water for a few seconds and added salt to it to use as a salin in my toddlers nose. was this safe? learning about all this bacteria that can live in water has me really worried now?

If you are using drinkable tap water that comes out of a faucet, I believe that boiling the water and cooling it down is sufficient to kill all harmful germs. If you are adding salt, you need to add an appropriate amount of salt, such as adding about 2 teaspoonfuls of salt to one quart of water( which makes about the same thing as what we call normal saline). Do not add an excess amount of salt.