Metered vs Timed

[PaulTH]

Currently I have a dual tank Fleck 9000 metered system. We have hard water and iron (don't know the specifics).

Our well is 400', pump is at 360 (might be 380 but don't recall), yield is/was 2 gallons per minute when it was drilled > 10 years ago, static water level is currently 60'.

Twice within the last 8-10 months we have run out of water. The first time was over the summer when we were experiencing a drought and I was utilizing an irrigation system. At that time we seemed to recover with a few hours....(immediately turned off irrigation system). The second time was about 3 weeks ago while we were getting ready for a vacation.....we probably did at least 4-6 loads of laundry over the course of 8-10 hours and I suspect the water softener also regenerated during this time.

I've had a couple of well guys come both of which stated that with 60' static we should have enough water in the well (300' x 1.46 gallons per foot = 438) to sustain peak water use. They recommended a larger tank to help offset how often the pump kicks on and also a low water shutoff to protect the pump when the well is low.

Not knowing if the well is still producing at 2 gallons a minute I question if their recommendations are enough.

Now to the water softener questions. I understand that having a metered softener is overall more efficient as it only regenerates when X gallons have been used verse a timed system which regenerates at Y time each week (regardless of gallons used) however; with a low yielding well, knowing I've run dry, my water use is only likely to increase (family) wouldn't a timed system be better as it won't regenerate during peak usage times? Are there any systems on the market that are both metered and timed, so after X gallons it will schedule a regeneration for the next defined tiem (e.g. 2am, when no one is using water)??

Any thoughts, help or suggestions greatly appreciated!
- PaulTH

 

[Reach4]

Are there any systems on the market that are both metered and timed, so after X gallons it will schedule a regeneration for the next defined tiem (e.g. 2am, when no one is using water)??

That is the norm for non-dual systems.

There is a regen time that can be set -- default is 2 AM. At that time, the logic checks to see if there is enough remaining capacity to go another day. If there is not, the system regenerates the. If there is still more capacity than the reserve, it checks again 24 hours later.

Do you have the mechanical 9000 or the 9000sxt with the digital display?

 

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[Mialynette2003]

Yes there are systems that regen only when set to as Reach4 mentioned. It is hard for me to believe you only have 2 gallons per minute based on the water static level and the well depth. A bigger pressure tank or holding tank will help a lot.

 

[Mikey]

...They recommended a larger tank to help offset how often the pump kicks on and also a low water shutoff to protect the pump when the well is low.

Sounds like good advice, but you need to know your well's refresh rate (or recovery rate) to determine how much water you can use over the long term. There's an important difference between how fast water can be pumped out and how fast it comes back in. You can pump out the 60' static water as fast as the pump can pump it, but the sustained yield depends on the well's refresh rate, which depends on the local hydrology. If the "2 GPM yield" is in fact the refresh rate (likely), that's all you can count on over the long term -- i.e, 120 GPH or 2880 GPD. If your pump pumps more than 2 GPM, you can eventually run the well dry if you try to exceed the refresh rate, which will eventually destroy the pump.

Pumping low-yield wells with conventional submersible pumps can be done, but requires specialized controls. One aerospace company measures the amperage of the pump’s motor in addition to other operating parameters. Very simply put, as a well pumps dry, the load on the motor changes; the controller senses the change and shuts off the motor as the head approaches zero. After a pre-programmed time, the controller restarts the pump. The pre-programmed time is determined by measuring the amount of time it takes for the well casing to refill with groundwater. This full refill time in your case is a little over 3 hours (438 gallons / 2 GPM), but you could program the time to match your above-ground storage capacity. Obviously, the larger your above-ground storage (usually the pressure tank), the more flexibility you've got in your pumping and usage, but there's no exceeding the long-term limits.

 

[ditttohead]

More storage is a great idea. You could also set the softener of other water treatment equipment to use the stored water as your regenerant water. You can have the pump fill the storage slowly, very common solution for this common problem.