I have a flourescent yellow one. Hes awesome, cleans my sand and everything. You have to realize.......they eat the bacteria in the sand.....not the detritus. I know it says they do.....but they dont. They do poop out clean sand though. They will stir your sand enough to keep it aerated and shifting. My lfs has 4 in his 125. The tank hit 94 degrees.......it crashed.....and the tiger tails didnt die. You just have to have a stable system. I killed my first one......but I got most of it out before it poluted my system. 50% water change and my tank was fine. (with some carbon too of course) Good clean up crew member.......but not totally reef safe.

sand sifting stars eat all the little bugs that stir up your sand. so your sand is lacking those little bugs and worms. you could grab a little sand from a friend? You want some good seasoned sand to re activate all your critters.

Live sand you buy in the store sucks. theres no other way to put it. That should work nicely for you. :)

Try some nassarious snails as well like 20-30 in a tank your size, they stir like mad and its funny as hell to see as pristine smooth sand bed and one lil tiny spec of food hit the water and they just come up out of the sand like snipers in gilly suits - -i have 10 in my 20long and could use 10 more they only get like 1/2 inchbut their cool, clean white in color and they'll clean the glass too