Now what? Gravel vac. & parasite ??s

*sigh* I've dosed Vitara twice for internal parasites now, and she still has white, stringy poop and no appetite. I gave a 25% water change, and then the second dose last night (or the night before? I'm a wreck...). She's being such a trooper just hanging in there! What should I do? Wait and dose her again when the package says I can?

I looked up gravel vacs on Big Al's online and found what I need (here's the stupid part...), and it just looks like a tube to me. Am I missing something? How do gravel vacs work? Call me stupid, but I must know.

Thanks, Spartan! I figured it was something like that. Do commercial gravel vacs have something to them beyond just a tube? Or would normal tubing work just as well?

Still wondering what to do about Vitara. I need to check when I can re-dose her. She's still not eating, and she isn't moving around much. :-/