Hey there,
I had 2 sand stars at the same time in a 60 gallon system. I was using a jaubert plenum system at that time, with live rock and skimmer, ph, sps/mixed system with a cuke that also cleans sand. One lived for around 4 years and the other one lived for over 7 years. Fed fish once every other day (mon, wed and fri). I believe that they will only eat live stuff and not clean sand is a myth. However I only have one in my current 120 gallon system. I have not heard that these stars are that controversial in a tank until last year... i got one anyway.... I do feed more often (twice every day), Now I am utilizing a refugium with chaeto, no plenum. So far, so good. We'll see how this goes.....