Strange! I went out to take a picture like you asked and tried one more time to open the valve just enough until water came down the slide like normal, and VOILA! the pressure on the tank is fine. If I open the valve on the pipe all the way (basically turn the handle all the way) the pressure goes up. I'm guessing that in previous years when the pool company opened up our pool for us, they probably never had the pipe opened all the way. I think it's all good for now, but if something weird happens, then I will re-post.