Question
QUESTION: I have project where I need to find an irrigation valve that will work with less than 5 psi. We a are taking stagnant water from a site 3,400 ft away and directing it to a 12ft tank. We will use this water to irrigate the plants on the site. I saw that you mentioned to someone a "mechanically actuated valve". Is there a particular brand you would recommend? I have been searching through many sites and haven't found any valve that will accept less than 5 psi. You mentioned the Rainbird DV-100 to the gentleman with the same problem, but it requires 10 psi to operate.

ANSWER: Thanks for the question.
The valve I was referring to is a electric actuated ball valve. "Spears PVC Fitting Company"  has a wide range of them. The principle is simple enough. You have a ball valve and rather than turning the handle by hand,  a small electric motor does it. I'll warn you, they aren't cheap, but well worth it if you can't find anything else to work. They are designed to work with 120 volt, but Spears does have other voltage options, at a price.
Another company you might try is "Bermad". The make many unique valves. I believe they too have actuated valves.
I know the DV's are suppose to only work 10+ PSI. I've saw them work at less though.
Try googling "SPEARS FITTINGS" you should get the site.
Good luck, if you need more help let me know.
Matt

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick reply. I called Spears PVC Fitting Company and they told me it would work, but as you said the cost is a little extream. The people at Bermad told me they have nothing that will work with 5 or less psi. However, they suggested a cheaper option, which was a pressure booster. They told me I could buy a pressure booster and it will allow us to use any standard irrigation valve. There idea was to have the pressure booster inbetween the water tank and the valve. I was curious about your insight into the use of a pressure booster. If you support the idea, is there a particular brand you would suggest. I have called a few companies, but none of them had anything that was more irrigation oriented (mostly residential).

Answer
This isn't right,
Your suppose to be learning from me not the other way around. The booster system is a great idea.  
I'll research a booster system for you, but I'll need a little more info. How much water flow do you need? Are you operating drip irrigation or sprinklers? What electricity is available? (power company, solar, etc)Finally, will this be a manual system or do you need fully automatic?
If you can give this info I'll give you a few recommendations.

Matt