How To Maximize Pump Flow

If you're looking for more flow to power a water feature, you may not need to "power up".  Optimizing the diameter of your tubing relative to your pump's maximum flow rating may give you surprising results.  Just because a pump has a 1 1/4" inch discharge outlet does not mean you should be using 1 1/4" tubing.  In fact, in many instances matching the tubing to the size of the discharge outlet will increase friction and decerease flow.  The table below shows the maximum flow for the most common tubing diameters.  You want to use the widest circumference tubing for your pump's flow rating.  For example, if you have a pump rated 3,000 GPH you should be using 2" diameter tubing (even if your discharge outlet is only 1 1/2"!).


* Source: Plastic Pipe and Fittings Association based upon maximum flow recommendations for Sched 40 PVC pipe.  
For those of you who need to know why - here is some quick math.  Increasing the diameter of tubing from 1" to 2" doubles the amount of static friction.  However, increasing the diameter of tubing from 1" to 2" quadruples the flow!