Thanks Tharbin,Welcome to R2R! AquaMedic pumps are hard to get in the US so I don't have direct knowledge of them. I do know that several people installed the 1.3 in Waterbox Peninsula 15s and they liked them. They were very quiet but I believe that they were also a little too powerful for the small 15-gallon Waterbox. Since it is a DC pump I would actually suggest the 2.3 for the extra overhead it will provide. This should also have enough extra head to easily power a random flow generator as well. DC pumps tend to run best at below 100%. I also prefer 4-5 times turnover for my return.
I don’t know much about DC pumps. I wonder for a pump rated at say 2000 lph what flow rate the pump would have at the max head height. Also, I wonder if I get a pump much more powerful than I need by tuning down the flow rate, does this mean it uses much less electricity and do these pumps have a minimum flow rate/electricity consumption. I need to do some research.