Who Gives A Fish Forums

Sand shouldn't be the issue then. Keep us posted on how the treatment goes. If it doesn't clear up in a week, you might need to look into other meds like Metroplex.

White, stringy poop can be a sign of internal parasites. Have you treated the tank with anything lately? I'd recommend PraziPro if you haven't already tried it. Also, how often do you do water changes?