I took ownership of a home with a pool and looking for some help. I'm new to pools and have no idea about pool plumbing. I can identify the pool pump, filter and heater. However, there are a couple of components I'm not understanding. Furthermore, I don't know if this is a saltwater or chlorine pool. Listing agent had no idea, the home was bank owned. I attached two pictures. The first picture has two components which to me would look like pumps but they only have one like to them as opposed to an inlet and outlet. The second picture I'm assuming it is a check valve?
Pool dimensions 40'x20', 3 feet shallow end and 7' deep end
Heater Pentair Mastertemp 400
Filter pump Hayward SP3020EE, Motor AO Smith ST1202, 2HP
Filter Hayward Pro Grid D.E Filter