Since this is algae related, I'm going to post this here and wait for others to chime in with their experiences.
I have used a solar cover in the past with great success, as does my SIL who now owns my old pool. My dad just had an above ground 24'x52" put in last year and says that he can't use the solar cover because he gets an algae bloom within a day. I had one other friend tell me years ago that she could never use a solar cover because of instant algae from the cover.
He told me he checks the chlorine daily and doses accordingly with the TF-100 that I insisted he buy and use the BBB (which he does) when he got the pool. His pool is currently 60something degrees and I told him he should put it on to warm it up and he said NO WAY and referenced the instant bloom.
Is there a reasonable explanation for this?