What should good used oil titrate at? what is the ph where we should look elsewhere? I am going to start titrating oils from different places tomorrow to see what values I come up with.

 

My oil has never titrated greater than 1.7, I would say anything at 2.0 or less is good. The other thing to look for is water, take some samples home and do a water test on them.
Quantitative Water Test - Collaborative Biodiesel Tutorial

 

looked at the link, the next question is how much water is too much?

 

I've done testing in my lab with a lab scale ( weigh sample, boil off water, re-weight ) and have found that anything over 2 percent water can cause problems. Excess water will combine with the Lye in a side reaction, which lowers the amount of catalyst required for maximum conversion, resulting in lower quality biodiesel. To much water, and you wind up with "glop-soap" If you use an "open" style of processor you can see the reaction and can "tweak" it a little by the addition of extra catalyst thereby saving the batch.