Di-Electric - Brass Nut on Steel Nipples

[Chefwong]

Got my Copper flex lines on hand and was just doing a rough eyeball on where to cut the lines, add male fitting, etc to plumb from in/out water feeds - flex - stock nipples on tank. In looking at the CU flex lines, I presume the brass nut where it connects to the steel nipple to the tank will eventually be the main place where it will corrode ?

So here I am back at square one.
I could either do what I'm looking at, which is CU flex lines to the Steel Nipples on the tank. The dissimilar metal will be where the brass nut is attached to the top off the stock nipples

If I hard pipe it, I guess I will get the same corrosion at some point but IMO, it may look -neater- with a ridged tie in
Stock Nipples from Tank
Female Bronze Adapter to Copper Transition (I have ProPress system)
Then ridged tie in back on the inlet/outlet feeds.

 

[Myhouse]

On the flex lines, is there a nylon thing between the brass nut and copper line? If so that is your dielectric union right there. Some flex lines that I installed years ago had that nylon thingy.