growing zoas

[Maverick00]

Ive had good success with growing most of my lps as well as some sps. The zoanthids seem to be the only coral that just doesnt appear to be growing or spreading over the last 8 months. I have two colonies that both look healthy and happy but these guys just wont grow! I target feed mysis shrimp/cyclopeeze and coral frenzy from time to time with the pumps off. I have tried moving them around the tank and that doesnt seem to help either. I was under the impression these are a relatively quick growing coral. Parameters are in check. Any ideas?