When are you planning on adding the nem? I'd let the tank age a few more months first after being re set up Bta's are not a natural host for this type of clown, but they will sometimes host them in the home aquarium and require less light. The natural hosting nems for ocellaris are ritteri, gigs, and mertans. I'm not too sure that the 2 x 150 MH are strong enough to keep these nems happy in a tank that size in less its placed up near the top of the tank. I'm using 2 x 250w 14k phoenix and leds on my 90g to keep my ritteri happy and he's all the way at the top of my rock work. I also have a rbta in the tank and my clarkii clown goes from one to the other constantly. As for getting your clowns to actually go into either of the nems thats just a gamble as captive bred clowns are just as apt to take up to your sand bed or lr as they are to a nem. which ever one you choose. If you have the room add both. Just remember that ritteri can get up to 2ft in length in the home aquarium and over 4ft in the wild. But i've also seen bta's up to 18" before splitting.