With a 250 MH light, you will want to start with the anemone a ways from the light and slowly work it up to that intensity of lighting. I would start off witht the anemone at least 3 feet from the bulb. If you happen to get an anemone from a tank that is already using a MH of that intensity, then you could put it the same distance as it is in the tank where you get it from. MH is intense and often times anemones aren't acclimated to that bright of light. If it is too bright, the anemone will shrivel and hide under rocks--not fun.