I dont't have one, but I have heard certain sea cucumbers do the best job.
One of the guys I deal with here recommended it to me when I asked him for a conch. The only thing is, I am afraid to put one in my tank as I have heard when they die, they tank your entire tank with them.You know.....Thanks for mentioning that! I forgot all about these. I have a Tiger Tail Cucumber in my tank as well! Have never once seen him since the day I put him in but I know he is helping with the sandbed as well.
No, Conches cannot nuke a tank. My post was misread. I was referring to the cucumber nuking the tank. WHen I went to buy a conch, they told me I should get the cucumber instead, but was afraid to do so because of it.