I have 2 spare tanks going besides the tank my Harlequins are in. My 135g tank & 5gal nano and I have put astrea stars in both tanks. I can take apx 10-15 stars out of both tanks a week to 10 days without depleating the astrea population.
There is no way I'm ever able to harvest enough astreas too keep my 2 harlequins well fed. I suplement their feeding mostly with chocostars. They love linkia stars but they get to be costly so they mabby get 3 linkias a year compared to 1-2 choco stars a month.
Cheers!