A) 0 represents the surface of the pool. B) The height of the pool is 10 above the pool surface C) It should be -3 since it is going down so it is going to be a negative number and it is also below the pool's surface.
You can't substitute baking soda with conditioner so don't add more conditioner becaue you'll not get fake snow. You should go and buy more baking soda.