Originally Posted by fishisfun7
What sort of salinity do they need and do they add to the bio load at all?
They will tolerate any salinity from 1.022 - 1.028 really, just do not adjust this number more than 0.002 in a 24 hour period. As long as you have live rock/sand they don't need to fed either. Actually, doing so can be detrimental to your water quality if you have no other filter feeders.
Make sure you place the dusters where you want them. After a short while they will permanently attach themselves to the rockwork and you will not be able to remove them without harming or killing them.
ps - every living thing in your tank adds to the bioload. However, the feather dusters impact will be very very minimal.