I see so many people adding so many led fixtures over there tank and I don’t understand why . I asked about lighting help for a new tank . It’s 72 x19x20 and I had someone say put 6 hydra 26 hd and T5 over it . What I don’t get is If I was going MH I would just put 3 250 Phoenix 14ks over it with two actinic. I would never put six . Are leds just that inadequate?
LEDs aren't "inadequate" per say. There is more to artificial lighting then just a label or a statement.
I've learned some here, believe me!!!
Experiences and observation can tell you a lot, and a good plan for that particular system will help you too!
The point is that every artificial light source will play a different role and will need to be addressed accordingly, for obvious reasons.
They all have their limits and own qualities. You need to consider all aspects and choose what you want.
You need to look at them and figure out what you want for your particular application.
My opinion?
I would say that you probably wouldn't absolutely need some MH systems over that tank due to it's depth, and a T5 only system would be great! If you want MHs/T5s that would be fine too! They would make it look amazing!
Others would prefer their LEDs and will advice you on that.
Bottom line is that we all look into it in different ways and with our preferences.
I just happen to be a MH/T5 kinda guy.

I agree with Daltrey when he says to skip the whole discussion on which lights are the best.
I think a bit of extra search is aways the way to go in order to determinate what suits you best.
There are way too many threads like this one already. I think many of us are getting tired of it.
It's aways exciting to build a new system. Enjoy!!!
Grandis.