These graph curves show pumps grouped by model.
(click gragh curves to enlarge them, then click the new image again to magnify it)

You will find the "sweet spot" on the graph curves by staying as close to the center of the shaded blue area as possible with the pump that gives you the desired gallons per minute and at the necessary head in feet. Click & view this example below:

Our site also offers the easier to use number curves (grouped by horsepower and by series). We simply transfered the information found on the Unitra graph curves (to the best of our ability) into the number curve format. These number curves should not be considered as an exact representation of pump performance but you will find the data to be "very close" and helpful in choosing the right pump for your needs.

Considerations for determining Total Dynamic Head (TDH):
1. Depth of water during pump operation (or the depth of the well if water level is not known).
2. Gallons per minute of water being pumped.
3. Pressure required at point of use.
4. Friction loss through drop pipe, and transport pipe.
5. Elevation rise or fall of transport pipe.
6. Devices, valves, fittings, restrictions in the system.
Refer to "Pump Sizing" and "Using Curves" for more information. You may also fill out the "Questionaire Form" and fax or email it to us for help.