Buy a few adults and keep them in a mason jar and feed them smaller aiptasia and once you have a decent supply of eggs and new hatches you can start to release them to the display , put them in at night is best when fish are sleeping and hiding , they don't last long cause they eat up their supply of food pretty quick and then starve out and die , a lot of times people fail cause they just dump in a few adults and hope for the best but if you breed them for a short period they work wonders , have used them many times over the years
If cost is an issue years ago several of us use to buy one each and have one person breed them like I mentioned above then split the pop later
After aiptasia is gone sell them to other hobbyist to recoup the initial cost
Hth