That is what I would consider the bare minimum for this species. Don't go lower. Give him some time to let him adapt to your tank and lighting. Right now he is stressing and doesn't have any zooxanthellae. You will need to supplementally feed him SMALL bits of food (no larger than pencil eraser size) while he recovers. Once he has his zooxanthellae back you won't need to feed him per se - unless you want him to get LARGE.
BTW - these are sexual creatures and do not reproduce asexually. Regardless of how large he gets, or what you read elsewhere, do NOT try to cut him in two - you will just end up with a dead anemone. If you are interested I have some scientific papers that detail sexual reproduction in this species, but they are kinda dry - not too many photos, LOL.
Here's another video that captures water movement for a healthy H. crispa. This again is pretty moderate for what I have seen them experience in the wild; they seem to like strong flow but not getting whipped around:
http://www.youtube.com/watch?v=lyjcPvOVcpY
And here's a cool shot of a light purple one with an A. tricinctus pair. That's a big anemone!
http://www.youtube.com/watch?v=j7frCwrVlsI