I would say water parameters in very good shape, preferably 0 nitrates, sg 1.026 to 1.027, temp 80-82F, preferably MH, though you could probably get by with the T-5 lighting you described. I would say 250 or even 150 watt MH is fine, assuming the anemone is fairly close to the light source. The tank should be well-established (at least 6 months preferably), a large, smooth surfaced rock for the anemone to attach to, and clowns such as ocellaris or perculas, as clowns are always found in H. mag in the wild. Also, feed several times each week with fresh seafood such as shrimp, silversides, squid.