A lot of us do lemon and lime all the time. The worst part of them is it is a little hard to get the ferment to start. Try making a starter with your yeast. Draw a cup of warm water, 100 degrees or so, no hotter than 105, add a little sugar and yeast nutrient. Let it sit for a while and add a cup or so of your must. Must is your grapefruit, lemon, lime, water and all the other ingredients in your fermenting vessel. Let it get fermenting good, mite take a while. Oh yeah, make sure your must is around 75 degrees or so. Anyway when it gets to fermenting after the cup of must, add another cup. In another hour or so add another cup. if it is fermenting strong after an hour or so, dump it in your primary. When it gets going good, give it a good stir, and then stir it two times a day or so. Keep oxygen in it at least til it gets down to 1.010. Check out Lon's site (skeeterpee. com.) that is more or less what you are going to be making. Arne