A well and two tanks . . .

[John Umphress]

New registered member here, but have been following/lurking on Terry's site for years.

Looking for some guidance on plumbing my existing well into a storage tank and moving water to a smaller tank used for drip irrigation.

Current setup: 435’ well, tested at 14-15gpm. Gould 2HP 10gpm pump at 400’. Model 233 pump saver and 85gal pressure tank. Went with the large pressure tank to keep the well pump from cycling so much. The pump and other equipment were installed just over a year ago and are working fine.

Modified setup: Have the Gould well pump fill a 3000 gal storage tank. A Flotec 1HP pump (230v) would move water to the smaller tank via 1800’ of 1.5” HDPE pipe. (15’ elevation rise.) When the smaller tank is full, the Flotec will be shut off via a float switch and wireless link at the smaller tank. A solar powered irrigation pump will provide water from the small tank to the drip lines. A 1/2HP Grundfos shallow well jet pump (230v) will provide water from the 3000 gal tank to the shop (and to the house when I get around to building it!)

Because I have 10kW of PV on my shop, I want to fill the large tank and transfer water to the small tank during daylight when I’m generating electricity. (I’m grid-tied, but the feed-in tariff is lousy.) Would prefer to have that happen sequentially – the well pump fills the large tank, THEN the transfer pump moves the water to the small tank. The idea is to run the well pump once per day. After the transfer, would still have plenty of water in the large tank for household use even without refilling from the well.

I will still need float switches in the large tank to control the well pump, as well as to activate the transfer pump and – maybe – to protect the jet pump if level in the large tank gets too low.

Am I missing anything here? Thinking maybe a Cycle Stop Valve or a Dole valve to ensure that the well pump continues to run while filling the big tank. And I guess I could plumb the jet pump to feed from both the big tank and the well, but prefer the tank as the well has some sulpher and iron.

Looking forward to ideas and guidance!

 

[Bannerman]

You said your well will maintain 14-15 GPM. Are you planning to use more than 14-15 GPM at any time? If not, I'm not understanding why you are wanting to complicate matters with 2 large storage tanks, 2 additional pumps, float switches, wireless links, etc.

Depending on the static level in the well and the flow rate needed for drip irrigation, it seems the well and 2HP pump should provide more than sufficient water for all of your intended uses.

A CSV will prevent the pump from cycling whether using 2 GPM or 10GPM even while using only a 4.5-gallon pressure tank. A CSV will also deliver consistent pressure and your well pump will likely consume substantially less electricity when water consumption is less than the pump's maximum delivery rate.

prefer the tank as the well has some sulpher and iron

As the water filling the tanks is obtained from the well, the water within the tanks will also contain sulfur and iron.

 

[Sponsor]

 

[John Umphress]

Thanks, Bannerman. Should have included that the drip field will be comprised of 1200 1gph emitters, so the system exceeds the well production. And since we have been in a dry period for the past 18 months, the well is producing around 9gpm at present. When the well was drilled, it was after a year of higher-than-normal rainfall. (Finally getting some rain right now.) And as our planting expands, we may add another tank for irrigation.

As for the sulfur and iron, the tank allows oxidation which eliminates the smell - not a small thing!

 

[LLigetfa]

the well is producing around 9gpm at present.

Is it the well or the pump producing 9 GPM? Big difference. If the pump can out-draw the well, you need to either limit it with a dole valve of CSV, or have robust run-dry protection, or both.

 

[Valveman]

With a 3000 gallon storage tank being filled at 14 GPM while drawing 20 GPM for the 1200 1gph emitters your good for 8 hours. Then you need to wait 4 hours for the well to refill the storage tank. But it sounds like a good plan. Really only need a 14 GPM Dole vale and a float switch for the well pump. The solar powered irrigation pump will just need to do 20 GPM at like 15-20 PSI as needed by the emitters and elevation and friction loss. You could use a Cycle Stop Valve or a complete PK1A kit on the jet pump for the house and buildings.

 

[Bannerman]

The solar powered irrigation pump will just need to do 20 GPM at like 15-20 PSI as needed by the emitters and elevation and friction loss

Perhaps this installation could be made less complex and more efficient by eliminating the 2nd storage tank and 20 GPM pump by dividing the emitters into smaller zones such as 2 - 10 GPM zones, each supplied by a timer controlled solenoid valve. Each zone could be activated in a alternating manner for 1 hour each for the required number of cycles per day.

The pump at the 3K gallon tank could then flow through a CSV to feed the home, shop and irrigation system. To supply lower pressure to the emitters, a pressure regulating valve calibrated to 15-20 psi placed before the 2 solenoid valves could be used.

Instead of using a jet pump to feed the CSV, a submersible pump placed within the 3K tank maybe a better option.

the tank allows oxidation which eliminates the smell -

Oxidizing ferrous iron and sulfur will result in ferric solid sediment that will accumulate within the 3K gallon tank. Unless the tank is equipped with a cone bottom and is raised to provide suitable access to a bottom drain valve, it will not be an easy task to clean out accumulated sediment on a regular basis.

Recommended to obtain a comprehensive lab test on your raw well water to identify the quatitiy of all elements in the water so as to assist to determine appropriate treatment methods. A test package frequently recommended in the Water Softener forum is the Standard Well package offered by National Labs WaterCheck. http://watercheck.myshopify.com/?aff=5

 

[John Umphress]

Is it the well or the pump producing 9 GPM? Big difference. If the pump can out-draw the well, you need to either limit it with a dole valve of CSV, or have robust run-dry protection, or both.

I'm guessing the pump AND the well. Opened a spigot closest to the well, let it run a while to drain down the pressure tank and then recorded the time required to fill a five gallon bucket. Came up with 8.7 gph.

 

[John Umphress]

Perhaps this installation could be made less complex and more efficient by eliminating the 2nd storage tank and 20 GPM pump by dividing the emitters into smaller zones such as 2 - 10 GPM zones, each supplied by a timer controlled solenoid valve. Each zone could be activated in a alternating manner for 1 hour each for the required number of cycles per day.

Growing lavender, so only the new plants will need to be watered regularly and just once a day. Older plants may get fertigated three - four times at the start of the growing season. Will be putting in 1000 - 1100 plants each year for the next several years, so will treat each season's planting as a zone. Re valves, would still need to run power or use solar or batteries to operate them.

The pump at the 3K gallon tank could then flow through a CSV to feed the home, shop and irrigation system. To supply lower pressure to the emitters, a pressure regulating valve calibrated to 15-20 psi placed before the 2 solenoid valves could be used.

Instead of using a jet pump to feed the CSV, a submersible pump placed within the 3K tank maybe a better option.

Having a jet pump external to the tank didn't strike me as a negative.

Oxidizing ferrous iron and sulfur will result in ferric solid sediment that will accumulate within the 3K gallon tank. Unless the tank is equipped with a cone bottom and is raised to provide suitable access to a bottom drain valve, it will not be an easy task to clean out accumulated sediment on a regular basis.

Sediment in the tanks is not such a bad thing. Would rather have it there than in my filters and clogging my drip emitters. In the 3000 gal tank, a couple of hundred gallons are below the outlet. Was planning on cleaning the tanks out on a regular basis. Will only irrigate/fertigate from late March to early October.

Recommended to obtain a comprehensive lab test on your raw well water to identify the quatitiy of all elements in the water so as to assist to determine appropriate treatment methods. A test package frequently recommended in the Water Softener forum is the Standard Well package offered by National Labs WaterCheck. http://watercheck.myshopify.com/?aff=5

Not a bad idea going forward. A lot of lime in the water (Texas hill country), which is not a bad thing if your irrigating lavender.

 

[John Umphress]

With a 3000 gallon storage tank being filled at 14 GPM while drawing 20 GPM for the 1200 1gph emitters your good for 8 hours. Then you need to wait 4 hours for the well to refill the storage tank. But it sounds like a good plan. Really only need a 14 GPM Dole vale and a float switch for the well pump. The solar powered irrigation pump will just need to do 20 GPM at like 15-20 PSI as needed by the emitters and elevation and friction loss. You could use a Cycle Stop Valve or a complete PK1A kit on the jet pump for the house and buildings.

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Cary, thanks. CSV seems to be a good solution, but may keep my big pressure tank as it's pretty new. (Space isn't an issue.) We're fortunate that the irrigation pump is at a slightly higher elevation than the drip field. And having multiple pumps doing different jobs doesn't bother me so long as they are well suited to the job and do it reliably.

 

[Valveman]

Cary, thanks. CSV seems to be a good solution, but may keep my big pressure tank as it's pretty new. (Space isn't an issue.) We're fortunate that the irrigation pump is at a slightly higher elevation than the drip field. And having multiple pumps doing different jobs doesn't bother me so long as they are well suited to the job and do it reliably.

The CSV will work with any size tank. If you have a goof tank use it no matter what size it is. Just don't need to purchase a large tank when you have a CSV and it makes you wait for the strong constant pressure from the CSV, but it will work fine otherwise.