I run a T5 setup with my corals. I have some that are doing straight amazing so far, my Duncan is growing a new head, my ric continues to flourish even though it has almost 0 base for over a week and was knocked all around my tank. I have 2 mushroom leathers, one I've had since my first corals arrived in the tank and it is doing well, standing tall and polyps fully extended. That is my green one. The other one I got last week and is showing signs of doing well as well, just adjusting. That one is purple. Cool thing is that when I bought both of them they were tan under LFS
lighting. I splurged and picked up a moon brain coral that has done well. I had him on the sandbed for a month and saw he was irritated and moved him this week onto rock.
Zoas were covered earlier too and I am gravitating towards the same mindset. They were open and looked fine for the longest time. They closed up last week and don't really want to open all of their heads. I moved them up another level in my tank hoping it would help. Colony has 15-20 heads.
As for the "weed" corals that I keep...My kenya tree was the first coral I placed in the tank. It has shown no signs of throwing more of itself around my tank, it has only gotten taller. The green star polyp...well I got it last week off reefs2go. It is still nothing more than looking like purple paste on a rock...I'll keep you informed on that.
You should return your T8 setup and get a T5. Pretty much everyone I have run into in the hobby runs them unless they are into SPS
and do metal or LED
setups...haven't gotten there and you aren't there either so I sure wouldn't be worried about it. T5 or bust IMO