To determine your your flow rate, there is an equation that allows you to
figure it pretty easily and accurately. You will
need a vacuum gauge
and a working pressure gauge
on your filter.
- The vacuum gauge should have a 1/4" MIP nipple on it. This is threaded into the front port of your
pump located near the bottom. Many pumps
have two, so be careful that you get the front one. This vacuum gauge will
read the inches of mercury that your pump develops when it is running.
The equation goes like this:
- The reading from the vacuum gauge is
multiplied by 1.13.
- The reading of the pressure gauge is multiplied by 2.31.
- Add the two together and you will get a number that reveals the Total Dynamic
With this number you must go to the flow rate chart for your pump. We
list the pump's flow rate charts on most of our product pages. If yours is not there, then the owner's manual
will have it. We also have most of the pump owner's manual on the product pages as well. You cannot use just any pumps
flow rate chart, it must be for your pump that you've collected the information above for.
The flow rate chart will have GPM at the
bottom of the chart and a TDH calibration with a range starting at zero and
going upwards on the left. Using the
number you calculated, travel upwards on the chart from the GPM, until you meet
at the intersect of the TDH number. That
intersect number is how many gallons of water and how hard it is pushing.