Hi all. I have a question. I went out to add chlorine and tighten up a small leak and noticed my pressure gauge is only reading about 4, it usually reads about 16. So, I walked up on the deck and the water flow coming out of the return is perfectly normal. Is this a broken gauge or possibly something more? The guage is original to the pool, so I'm guessing around 4 0r 5 yrs?