If you want to change it for just the recipe you're working on, click on the check marked box next to the mash profile near the bottom of the design page, double click on the saccharification step and change the figure in the water/grain ratio box. Once you've done this you can add it to your profiles by clicking on the save box next to the mash profile. I suggest you go into the mash profiles and delete the old profile after making the changes.