i have a 60 gal corner reef tank. started with 5 snails to control the algae. now have snail eggs, little purple spots ALL over the tank. the tank is as healthy as i have ever had. i am just tired of scraping them off the glass every weekend. they took the algae away, but now they have little egg nests everywhere. worse than the red algae was. and they are not easy to scrape off. the wife has to take over after 1/2 hr. tank is fairly deep, she needa a stool to reach. this is the best fish site i have seen yet. thanks for anything