Our pump failed last Friday, right in the middle of a 95+ hot, humid heatwave. I was very nervous about maintaining the pool with such heat, in the face of a broken pump, particularly as we had a lot of sun during the course of the following week, as well as 3 serious downpours. I figured the best I could do was test the water daily and add bleach to get near the top of the FC range, and use a net to skim the surface.
A week later, we had a functioning pump and I decided to shock the pool, just to be safe. I was thrilled to find that we had no FC loss overnight, no CC and a crystal clear pool (once I vacuumed).
The bottom line is that a broken pump does not have to be devastating. Vigilance as to FC levels, with a little bit of manual surface skimming, can make the start up relatively pain free.