Recently my DNA electrophoresis gels have started looking strange (see attached image). I find this very perplexing since I haven't modified my technique, and up until this point they've been working fine. Gels are currently prepared and run with 1x TAE Buffer, 1.5% agarose, and 1ul GelRed/90 ml 1x TAE Buffer (added right before pouring). Gels are run at 100 volts for 30 minutes at room temperature.
So far I have tried: new ladder, prepared fresh buffer (using two different sources of millipore water), and run the gels in a different box.
Can anyone thing of anything else I can try to resolve this issue?