Random Algae

Hello All,

I had a new liner installed in April. Dark blue, previous one was white. I use the BBB method and never any problems. This year, even with proper CL levels, etc.. I get some minor algae patches in different areas of my pool..Water is and has been crystal clear.. I even upped my pump time ad speed, and still I am getting little areas..
light, at the wall transitions, etc....As said, Ph, CL, everything is spot on...I have shocked it a few times just to be sure. The algae shows at different areas everytime it appears, so it is not a circulation issues...I hate adding more chems to my pool than necessary..but is algaecide my only option?