I agree annoying little sessile snail but reef safe in most cases.The only time it's considered a pest if the web is draped over a coral keeping them from opening completely.
well I can't post pics up yet my cpu is down I only have internet at my parents and to boot no high speed down my road yet. but there isnt a program on here to resize pics and i dont want to download on to someones elses cpu. anyhow there is no visual tubes that i can see but will look again and it is off plants and rocks my wife thinks I brought home water spiders. wish I could get a pic