For uniform gels, your agarose must be must be completely dissolved and free of any particles. Remember that agarose is a long-chain polymer and takes some time to fully dissolve into solution. A good way to check your gel material is to carefully swirl it while holding it up to the light to look for any “glass-like” particles that haven’t dissolved. Continue heating until the gel looks clear, like water. Remember to compensate for evaporation as continued heating will cause your gel% to increase. When the gel has been dissolved, cool it to approximately 60°C before pouring into the gel tray.