My protein size is 17 kDa, and I cast a 20% gel. When the ladder started to resolve, we changed the voltage to 120V, but after some time, the ladder got stuck at one point, and the dye front became distorted. I noticed a bubble kind of thing inside the gel, and it seemed like it started melting. When I took the gel out, it had a crack and was curled from one end. So, for 20% gel, should I run it at a lower voltage?