Earlier tonight I mixed my lye solution (all NaOH) for three batches I'm doing tomorrow. When I went to cover them for the night two were normal and one had a crust on the top. There was nothing added to the water in the crusty batch - the other two had sugar added. This is the second time this has happened this week, and both times I was using a higher lye concentration. This batch had 132 grams of distilled water and 86 grams of NaOH. The other one was similar. Both of the solutions that formed a crust were left to cool to room temperature, but so were the others that have been fine. I stirred the crusty layer back into the solution and I can see floaties in it. Two questions - why do you suppose this happened, and is it ok to use or should I mix up the lye solution again.