How to transfer & pressurize very low volume of water from a 2,500 rain water tank

[Pumper]

Trying to set up a 3,000 gal. water tank system collecting rainwater off 2 gutters. Goal is to collect and transfer rainwater to 10 gph Aquafog, a greenhouse cooling fogging fan that will be mounted high in the rafters. Any ideas?

Seems I need to run a line with a on demand pump to a small bladder tank and then out to the fogger's inlet.

 

[Banjo Bud]

Can’t you just pump it directly from the collection tank to the fogger without pressuring it in another tank? I have a 1000 gallon collection tank buried in my yard and I have a sprinkler pump that sits about 30’ from that tank. The pump sucks from the tank and pushes directly out to my sprinkler heads. No pressurized tank. The pump does the work. It pumps at 40 psi. I was told by the pump company (Red Lion) that even at low volume like 1/2 gallon per minute, the pump would not burn up. Not sure about 10 GPh though.

 

[Sponsor]

 

[Reach4]

4o to 60 psi pressure wanted, or what?
Is there a drain pipe in the bottom of the tank, or will you use an access opening up top?

I am thinking of a 1/2 hp 10 gpm submersible. That size is usually the cheapest submersible. The flow inducer is just a piece of pvc sewer pipe. The purpose of the float switch is to turn off the pump if the tank runs low of water. There would also be a pressure switch and a pressure tank.

If you had a bottom output, or even not, you could use a different kind of pump that is not in the tank. The submersible will consume less electricity, but you could use a jet pump outside of the tank. Since a 32 gallon pressure tank holds about 8 gallons, your pump would only run about every 48 minutes anyway.

 

[Valveman]

Like Reach says you need a pressure tank and pressure switch. Like Bud says, you can use the same pump with the same pressure tank that supplies everything else. But you cannot run 10GPH without a pressure tank/pressure switch, as that is not enough to keep the pump cool.

Bud, do you have that in writing from Red Lion about their pump working fine at 1/2 GPM? I know that is correct but would like to see it in writing from the pump company. They usually won't admit their pumps work at that low of flow rate.

 

[LLigetfa]

It would help to know what min/max pressure this Aquafog system needs. If a pressure tank is required, then a larger tank is better as it reduces the number of cycles.

Possibly, you could just return a potion of the flow to the holding tank and forego a pressure tank and switch. As @Reach4 said, a submersible would consume less electricity and choosing one that does not have floating stages might use the least. When selecting a pump, don't look for the lowest GPM rating but rather the HP. If you compare two 1/2HP pumps, the one with lower GPM is designed to push water from a greater depth and will have too much pressure output from a shallow depth.

 

[Banjo Bud]

I like llgetfa’s idea of pumping it back into the tank. You could just use a ball valve and adjust it until it’s right.

 

[Reach4]

Run the pump continuously to provide 0.167 GPM, to avoid using a pressure tank with pressure switch? I would not do that.

 

[Pumper]

Can’t you just pump it directly from the collection tank to the fogger without pressuring it in another tank? I have a 1000 gallon collection tank buried in my yard and I have a sprinkler pump that sits about 30’ from that tank. The pump sucks from the tank and pushes directly out to my sprinkler heads. No pressurized tank. The pump does the work. It pumps at 40 psi. I was told by the pump company (Red Lion) that even at low volume like 1/2 gallon per minute, the pump would not burn up. Not sure about 10 GPh though.

Is your pump an on demand pump? Again, I'm talking a max of 1 qt./minute and as low as 1/2 pt., all depends on my cooling needs at the time.

 

[Pumper]

View attachment 59616

Like Reach says you need a pressure tank and pressure switch. Like Bud says, you can use the same pump with the same pressure tank that supplies everything else. But you cannot run 10GPH without a pressure tank/pressure switch, as that is not enough to keep the pump cool.

Bud, do you have that in writing from Red Lion about their pump working fine at 1/2 GPM? I know that is correct but would like to see it in writing from the pump company. They usually won't admit their pumps work at that low of flow rate.

The tank is a your typical Norwesco rainwater collection tank. I have a 305 gal. under one gutter (left side) I'll link up to the new tank under the right gutter. The tanks have a 2" drain at the bottom and a 16" manhole screw on cover at the top. My fogger will hang in the rafters at about 10' high. Columns are 10'. Required PSI is 10 - 100 for the fogger. https://www.jaybird-mfg.com/products/gt-500-series/gt-500-direct-feed/

They also make a 3 gal. hanging sump but I think I'm back to where I started regarding the ultra low volume. https://www.jaybird-mfg.com/products/gt-500-series/gt-500-hanging-sump/

I need to figure a way to get it into a bladder tank and let the pressure do the rest.

In case any one is wondering I graft/grow/produce avocados, mangos, citrus and other tropical fruits in central Texas as a hobby.

Thanks for the feedback. Sorry it took so long to check in.

 

[Valveman]

I need to figure a way to get it into a bladder tank and let the pressure do the rest.

I agree. But at 10 GPH you still don't need a very large pressure tank. A 20 gallon size tank holds 5 gallons of water, which would only cause the pump to come on twice per hour. A little jet pump like a J7S and a PK1ALT with a 20 gallon tank would supply the fogger and anything else you wanted as well.

 

[Pumper]

I agree. But at 10 GPH you still don't need a very large pressure tank. A 20 gallon size tank holds 5 gallons of water, which would only cause the pump to come on twice per hour. A little jet pump like a J7S and a PK1ALT with a 20 gallon tank would supply the fogger and anything else you wanted as well.

I agree, only need a very small tank. Thanks for the info, I'll check them out.

 

[Pumper]

What is the PK1ALT?

 

[LLigetfa]

I fail to see how a CSV would help in this case. The pump will cycle more often than on a large tank. Filling a small tank at 1 GPM when the draw is much less than that won't keep the pump running and won't reduce pump cycles.

 

[Pumper]

This might work perfectly. Comments please? https://www.homedepot.com/p/TALLAS-...-Pump-D-BOOST-1100-45-115-120V-60Hz/310259923

 

[LLigetfa]

You don't need a 3/4 HP motor for so little draw but what you do need is a larger tank.

 

[Valveman]

I fail to see how a CSV would help in this case. The pump will cycle more often than on a large tank. Filling a small tank at 1 GPM when the draw is much less than that won't keep the pump running and won't reduce pump cycles.

The CSV1A only fills the last 1-2 gallons of any size tank at 1 GPM. If the fogger is the only demand, the CSV will not be helpful. But the CSV will let you use other water in the green house as needed as well as run the fogger from the tank.

The PK1ALT is a kit that has all the controls needed for the pump except the pressure tank. Then you can add a 20 or 44 gallon size pressure tank as desired. With a pump like a J5S this system will last a lifetime. Or you can use one of those 3/4HP all in one things and replace it many times in your life time. Either one will make the foggers fog and let you run a garden hose or sprinkler.

 

[Banjo Bud]

Why won’t a Shallow well pump like a Gould’s J5 work if you split the pressure line from it and pump most of it back into the rain tank and just a little to the fogger line?

 

[Valveman]

Actually a jet pump will work fine down to about 2/10s of a GPM. And yes recirculating the excess would work. With a pressure tank the pump would run 2 minutes and be off 10-20 minutes instead of running all the time.