Help with bad electrophoresis run. - (Apr/04/2013 )

Im having an issue with my electrophoresis. For some reason the DNA is not moving down the gels as fast as it should. Im having to run the gels for about 20 hours (instead of the normal 3-4 hours). I changed buffer, gels, power pack and tanks and it still is having the same problem. Could the DNA fragment size be too large making it moving slowly? Does anyone know what the reason is or could be? Any ideas would be appreciated, thanks.

What is your gel percentage? What is your DNA stored in? What is the size of your DNA? Does your loading dye have this same effect on other fragments?

wire for electricity in the tank might be dirty - gently run the finger threw it...

and need an answers to the questions of jerryshelly1.

may also be buffer leakage