but remember.... at such low flow rates the diameter of the tubing renders much less virtual flow resistance than it would for, say that 170 Gph.
or to put it in another way.... the effects the 1/4" tubing has on the 170 GPH pump's performance, is much more than on the 20 Gph pump. Granted, the 170'er might FLOW more, but it's going to work a lot harder, thus the amount of heat added per GPH gained, might actually make it loose against the 20GPH when all is said and done...
then there is my favorite saying......" it's not how much you flow, it's what you do with your flow...."
I don't want people to think I'm anti high flow.... on the contrary.... am the one that sticks two 400GPH pumps side by side into a space smaller than what's needed to U-turn a nanobot.... well almost
you know like this
Picture.