tang eat sand?

[popper]

1. The pbt in qt no longer shows any sign of ich. Should I leave him there for longer or safe to transfer back to dt?

2. In the bare bottom qt, after I add the pbt. A day later, I noticed sand. sand in the tank. I removed the sand. Now about 7 days later, there's more sand.

Could it ate the sand from dt and poop out in qt?

 

[Bruce Spiegelman]

How long has he been in QT? Was he in the main DP first?

 

[popper]

It was in sanded display for several months.

Been in qt for maybe 8 days.

 

[Kensington Reefer]

Lots of the Acanthurus tangs graze the micro fauna on the sand bed
The result is sand in the feces

 

[Bruce Spiegelman]

It was in sanded display for several months.

Been in qt for maybe 8 days.

Then he still has Ich and always will. PBT's are Ich magnets and (or course) it is now present in your DT. Moving him to the DT now though would stress him again and that's when they go full blown outbreak often. Give it a bit more time before you put him back.