koralia Nano 420, or K2??

[SteveySingle]

I have a 17.4 Mr. Aqua rimless. I have a K2 laying around and also a nano 420 in the mail.. do you guys think the nano would suit the tank just fine or should i do the k2, or..both? tell me what you guys think

 

[AZDesertRat]

I have both a Nano 425 and a K1 along with a modded AC-110 HOB refugium on my 16G bowfront and would like even more flow even with the 2" Southdown sand bed it has.