enter image description here

For irrigation, we have about more than 50000 L of large tank and the outlet of 2 inches (thick red - high pressure) goes through the ground for drip irrigation. Now I need another small tank of 200 L with some liquid(nutrient for soil) to be added along with water. Though the outlet of tank B will be 1/2 inch, the water pressure(in drops) will be control using a gate value. Since the existing water flow is very high pressure, just directly connecting the outlet from tank B to the existing water pipe may result in water being pumped into tank B.

Though in picture, the position of the outlets are in middle, actually it will be in bottom.

Will check valve be the solution here? Since the outlet flow from tank B will be drops and the from tank A it will be very high pressure, could the valve open so that those drops will get mixed with existing water flow?

If check valve is not the right one what should use here?

  • Can the nutrients just be added to the large tank? A check valve won't work as it will never open because of the pressure from the large tank.
    – JACK
    Commented Aug 13, 2020 at 15:08
  • @JACK The problem is there are few other outlets in tank A which we use for bathing, washing dishes and clothes etc. so the nutrients can only added to the outlets used for irrigation.
    – Gopi
    Commented Aug 13, 2020 at 15:17
  • Where is your high pressure coming from a tank 30’ high would only have about 15 psi.
    – Ed Beal
    Commented Aug 13, 2020 at 23:10

2 Answers 2


Please Google "venturi fertilizer injector" to learn about this technology. It is a device that works with no electric power. The flow of a large amount of liquid through the device creates a vacuum that will suck a smaller quantity of a second liquid into the main flow.

In this case you would use a check valve on the small tank to prevent backflow in case the main flow stops. No flow = no vacuum, which could cause backflow if there is no check valve.


I believe your plan will not work as the "B" tank will almost never have enough pressure to flow into your line. Even when it does the rate is going to be quite variable.

I think you need a "mixing valve" which may require a pump for tank "B" so that it's always able to overcome the line pressure from "A".

Your best bet is probably to contact a local supply house and see if they have some advice. Alternatively you may want to consult an engineer experienced in such systems and get their recommendation.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.