How much do sea cucumbers actually help?

[AdamNC]

I've had my Tiger Tail for well over a year now and it even has split on its own once. The only issue I have is they both like to take sand from the front and "move" it to the back of the tank. Other then that I've had no issues with them, even 2 in a 29 gallon.

 

[Ffvince]

I have a Black Sea cucumber for the past year or so, I wouldn’t say he’s a great cleaner but he does clean the tough areas between the rocks and sanded. He’s never in the open or just sand sifting... very slow moving about 6 inch’s in a 200g. Overall I think they are a good addition to a cuc but not a necessity...

 

[bubbaque]

I ended up adding three of them and not sure they help much. My sand is white but I think it's mainly from the diamond goby.