1/2" to 0.5mm valve?

[mrhasan]

I have finally got an JBJ ATO (Yappy! Got tired of topping off). The pump that I got with it (maxijet 1200) has a 1/2" mouth. So I bought 1/2" pipe and fitted it with the maxijet and the other end on top of the tank (duh! ). Kept it outside water so that no vacuum suction occurs. But the flow from 1/2" is a bit too much for my tank so I was thinking of putting a valve in between and take a 0.5mm tubline out which will throw in water.

So is there any sort of valve for 1/2" in and 0.5mm out? Or which sort of valve do you guys recommend?

I am not turning on the pump till I get something to control the flow.