Does anyone know of any useful techniques or technologies to find a small leak in a swimming pool liner?

Would be interested to discuss two cases:
Case 1 - you don't have any idea where the leak is.
Case 2 - you have several ideas of places that look suspicious and you want to confirm whether there's a leak.

Regarding case 2 - I tried colored saran wrap. I thought it might stick tight to the area of a leak. It didn't, so either not a leak or not an effective techniques. I have about 6 suspicious places so I really don't want to start patching them without confirming which one is causing my problem.

Don't want to talk about draining the pool.
Thx for any ideas.

Hi Pete,
I have looked into this electronic leak detector, but don't remember how much it is:
http://www.leaktools.com/individual/vinyl.htm
I have had success finding leaks in my pool by locating the suspect locations and using food coloring (typically at the corners and along the bottom of walls). I put on a mask and dive to the suspect location with a small squirt type bottle of food coloring and squirt it near the suspect hole. If it is a leak, the coloring should migrate to the leak. I have heard of people dumping a whole quart of coloring in the pool and watching to see if it migrates to a specific point but I think the leak would have to be pretty big for this to work. (Note: for the food color trick to work, the pump must be off and no wind rippling pool surface!)
I also once thought I would make a leak detector like the one in the link above, but found the leak before trying it. I think it could be done with a good digital multimeter, one lead to a ground stake near the pool and the other on a pole to stick in the water.

Thanks Ed. The device at the link is $1000+ which is more than I wanted to spend.

But I like your ideas about food coloring or trying to imitate what that leak detector does (hopefully without electrocuting anyone).

I had the same problem, losing about an inch per 2 days, and despite close underwater inspections, I only found the leak from a mark on the wall when we dismantled the pool. The liner had given 14 years of service, and had been patched above the waterline where I think it had been sun-affected. (I built a shed in its place!). Not much help, but the liner life we got may be of interest. Ray