U can make Same pump have diff flow rate

Ok this seems incredibly odd and I can not understand why but I was running a Rio plus 2100 return pump on my sump with 3/4 inch return hose and I was getting about 350 gallons per hour at 4 feet.... I decided to switch to a 1 inch hose just because I had a new return jet for one inch hosing... I cut the same amount of hosing 4 feet exact and now my return pump has got to be running at almost double the flow I'd say at least 650-700 gph!!! How in the world did this happen is this normal and can anyone explain the drastic increase in flow just by using an extra 1/4 inch tubing with same pump.... I may just be an idiot and I'm the only one who didn't know this would happen but the box of the pump even says 350 gph at 4 feet and I'm getting way more than that now can someone explain this to me please... Sorry if I'm just being a little slow here but I just can't figure y it would double the flow rate obviously it's a bigger tube but how can that afffect it if anything I thought it would decrease guess I'm just an idiot what can I say!

 

I'll find a link for you, but i think magdrive quotes using 1 1/2" for the return for appropriate return GPH... using bigger hose is always a plus.

 

Simple... kinda.

Head pressure and friction.

The larger piping reduces the overall head pressure applied to the pump, allowing it to pump more GPH. It also allows more water to pass without touching pipe walls, thus reducing the friction... although this is very minimal compared to the Head Pressure.

 

Thanks for the responses so I guess it's a known fact that if u use ABOVE the reccomended hose barb fittings and hose that u will get a higher gph... I could have gotten a lot more use outta pumps if I woulda known this earlier in my days.... Thanks guys

 

Pretty much all pump companies recommend oversizing the tubing or piping to reduce friction losses. Mag has always recommended this.

When using barbed nipples and vinyl tubing this is especially important since the inside diameter of the barbed fitting is a huge reduction in inside diameter, I always step up at least one size if not more to overcome that.