Yeah we need some electronics guys to figure out the circuit mod needed to bring those basic D-5's up to setting 5 or more..
As far as series vs. parallel, for a typical water cooling setup, you'll always gain more from running in series, we just have too much restriction for the other to work better. Not to mention running in pararallel would require at best some Y splitters and/or a multiport reservoir to feed and combine those flows.
When you run pumps in series, you stack the pump curves vertically so you effectively double the pressure per flow rate, but you have the same maximum flow rate. When you run them in parallel you effectively stack the curves horizontally or you double the amount of flow rate per pressure unit. Parallel will double your maximum flow rate, and give you the same maximum head pressure as one pump.
The end result of the comparison makes running in series better when a system is more restrictive, and would make parallel better when using a lower restriction. As it turns out a typical water cooling setup is generally better fitting of the series condition because it is on the more restrictive side of things.
I should look into simulating a system with an MCW30 and a PA160 and 1/2" tubing. That might just be free flowing enough to where parallel would be better
Not that you would ever do that!!!