I agree that the borates are probably the best insurance -- they are a mild algaecide so might not prevent algae completely if the FC gets to zero, but they'll certainly slow down the growth enough to prevent things getting really bad and along with regular chlorine should help against tougher types of algae.

One other algaecide approach to Ben's list is an ammonium product such as ammonium chloride. With chlorine in the water, this creates monochloramine which kills algae (at least green algae; I'm not so sure about yellow/mustard algae, not enough experience with that). The main advantage with the monochloramine approach, unlike the sodium bromide, is that you can get rid of the monochloramine by adding more chlorine. With sodium bromide, it can take some time to get rid of the bromine, though by not overdosing it might not take more than some number of weeks and having a bromine pool is not a disaster (mostly it's just a higher chlorine demand for a while).