Under the lighting you've got with good reflectors you can grow hairgrass and glosso (as I am!), but I would try them without CO2. I have E.tennellus growing brilliantly and have grown that, and Marsilea crenata, in lower tech tanks in the past with decent success, but I'd really try and get CO2 in. DIY with yeast and ladders are better than nothing IME. I had a yeast unit and dosed Easy Carbo as well on my nano with pretty good results in the end, but for a 180 you'd be best with 2 or 3 bottles and change them on different days to keep a more stable CO2 level.