Watts per gallon is pretty outdated.You think its 2 much light its not even 3 watts a galoon and will my substrate be fine
I'm not real up to day on T5 fixtures. However, a single bulb Hagen glo comes to mind. I think the light will still be a little high but it comes with a hanging kit. If you are ok with hanging it, then you could raise it up to get the right intensity. If you are just going to have it right above the tank, a single bulb T5NO fixture would work but I have no recommendation for that.Well I havent ordered the light yet have any better ideas max I can pay is 90 for a 24 inch fixture.