This is a really minor problem but here it is anyway. The current GUI for the electrolyzer doesn't have the input and output box in the right places. The code specifies it for x location while the picture shows them in y location. The easiest way to fix this was just to change the picture. Below is the corrected picture that I created. For those interested you can just put this picture in your IC2sprites folder within the minecraft.jar file now. Just make sure it is named GUIElectrolyzer.png so that it will overwrite the old file.