Valve for slow dosing

[brad]

I would like to constantly drip vinegar into my sump. To do this, I'd need a very very very slow drip rate. Something similar to the needle valves used on calcium reactors could probably work, but I'd prefer something not made of metal.

I also drip lots of other stuff, and currently am using a $6 valve from lowes, so any advice for anything better would be appreciated.

 

[leveldrummer]

dosing pumps are made to do exactly what your looking for. expensive, but accurate and for the most part, accident proof.