I'm adding a pool heater and going to take the opportunity to re plumb my equipment and upgrade my valves. Currently I have a Haywood DE filter with a push pull vale and cheap potable water ball valves on the skimmer and main drain returns. I'm thinking I will put a 3 way between the skimmer, drain and main pump and a multiport on the filter.
Do I need valves before or after the heater?
Do I need a specific multiport to fit my filter or are they all common size?
I see different price levels of multiport. Is this a quality difference or is there anything else I should be looking for?