bottom line, the only way copper will come out of your pool is as stain. Good news is that if you only dosed one time with a copper algaecide then there is not enough copper to make any noticeable staining. The problem arises with repeated use. The copper stains out on the pool and then, for what ever reason, the pH drops and the copper redissolves and you have copper levels that are very high (and swimmers with green hair). You can add a sequestrant like Jack's Magic Blue Stuff on a regular basis to keep the copper chelated and in solution but this often deactivates its algaestatic properties.