Set up I have a 32/32/64 tent and 175w Mh light

[Zx10]

i have a 6in duct fan and wondering how high above plants that have been under a t5 should I start with my 175mh light.

The plants are kinda banged up and small between 3 1/4 and 4 1/2 inches. These were very old seeds so I don’t expect much. More of a test run.

 

[Zx10]

I have a 5 in reducer on the 6 in fan and it feels like the exhaust side is blowing back as much as the intake in the tent, any suggestions?