Tanks to small for hosting Anemones, would be fine for smaller ones like Curly q's but then corals would be out of the question - the nem's would kill'm. Also it's gonna be tough to keep coral friendly water parameters in 15 gal with 3 fish - you'd be changing water everyday and even then no garuntees.
Your water flow should be at a min. 10x the 15 gal - so 2x hydor nano's rated @ 75-100 gal per hr saltwater. Purgien in the HOB is a good option so is chem-pure elite. Most of the corals, esp. stoney's get too big for 15 gal + 8w lighting - your light and tank would be fine for mushrooms and ricordea corals.
So even with the 3x6watt led's plus the 8 watt factory bulb there is no chance of any corals? I'm confused. One minute you say no corals, then suggest some. You say no anemone, then suggest one that will eat the chiral you said I can't have. So instead of you can't have this or that, could you please tell me what I could have. If it was your tank, what would you put in it? How would you set it up?

