Tuesday, February 10, 2015

What Problems Will I Have If I Do Not Have Enough Flow Rate to Backwash My Iron Filter?

I am interested in your pro-ox iron filter. I am having trouble determining the correct flow rate. what problems will i have if i select a size filter with a lower flow rate than my pump? 

Paul Celona

Hello Paul,

Thank you for contacting us through our website.

Did you try the flow rate calculating instructions that we have on our website? Here are the steps in case you haven’t seen them:

How to determine flow rate for wells with pressure tanks:

It is easy. All you need is a 1 or 5 gallon bucket and a watch or clock! It takes just a few minutes. Just follow these steps:

1. Open any hose bib or faucet until well pump turns on.

2. Close hose bib or faucet and let pump fill up pressure tank until well turns off.

3. Using a 1 or 5 gal. bucket, open faucet, collect and measure all water discharged until pump turns on. NOTE: You do not have to fill the buckets as fast as you can; simply measure the water.

4. When pump turns on, immediately close faucet and start timing pump cycle in seconds until well shuts off.

5. Divide the number of gallons collected in Step 3 by the number of seconds in Step 4.

6. Multiply the answer from Step 5 by 60.

7. The answer in Step 6 is the average pumping capacity of the pump in gallons per minute (GPM).

Now, if you have tried that and are still having difficulty in testing the flow rate for whatever reason, your best bet is probably to just open up an outside faucet and simply time how long it takes to fill a 5-gallon bucket, that should give you a rough estimate of what you have to work with.

Say that you were to select a Pro-OX iron filter like the 1.5 CF size, for example, which requires ten gallons per minute to backwash. As long as you can provide ten gallons per minute of flow, the system will backwash properly and continue to work a long while. If it were to turn out that your well only produces around 7 gallons per minute, on the other hand, then the 1.5 CF system wouldn’t be able to properly backwash. Eventually, if the backwash water is insufficient, then the media bed can foul, and the iron filter will stop working. This would lead to pressure loss and an inability to remove iron.

So really, it is important to be fairly certain of your flow rate when sizing the iron filter. If you only have 7 GPM to work with, then the 1.0 CF is the best size to use.

Below are a few pictures showing an installed Pro-Ox iron filter, a schematic diagram outlining this installed system, and a dirty well hydrant flushing.

Please email us at support@cleanwaterstore.com or call us back with any questions, we’ll be here to help you out.