I have two ball valves at the suction header of my pump. My guess is that one of them is for the line from the pool skimmer (top of the pool) and the other one is for the line from the main drain (bottom of the pool). One of them is open (one on the left) while the other one is closed (one on the right). Ever since I moved into my house (aka took ownership of the pool), the valve positions (on/off status) have remained unchanged.
Is this how it should be set-up typically? Assuming that my understanding of the piping configuration is correct, is there any reason I cannot have both valves open and take suction from the skimmer line as well as the line from the main drain? Is there any advantage of switching the suction sources?......take suction from the main drain only?
I would very much appreciate a detailed explanation on what the recommended set-up should be.
Thanks in advance.