Do you have any other stock yet? If its still new I would say its just going through the uglies. All new tanks do so be patient, it's not pretty I know! For your info, in the future a clean up crew doesn't solve algae issues, they help but are no cure. Excess algae is due to poor water conditions, too much food, too much lighting, not enough water changes etc. If I were you I would add you first fish (if you haven't already) and perhaps a snail or too, slow and steady wins the salt water race