I was away for the week and left my wife in charge of adding bleach. She was somewhat lax on the adding bleach schedule. Came back and had a slight algae issue. Along the bottom of one side of the pool where the wall meets the floor for about half the length of the pool there was algae in the crevice and a few other small areas on the walls. The water was clear though. I vacummed, brushed and added chlorine. I did not shock. This was on Wednesday. There has been no sign of anything since. Water is clear and sparkly. Just wondering if there is a hidden enemy waiting. Do you have to shock or is it possible it was caught early enough and I took care of it with my procedure. Overnight FC loss looks pretty normal ~ 0.5 ppm loss.