First I have 4x4x6 grow tents with carbon filter ventilation 2 fans and a dehumidifier. I run a 200-600 super lum HID lighting. I grow autos so they are short plants. What is the best distance from light to plant? I’m beginning to think even on 200 the plants are getting burnt. Any advice would be greatly appreciated
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don’t go by height alone. you need to measure PPFD to figure out how many photons they are getting.
step one, read the thread to understand DLI
step two, get the Photone app.
step three, measure and adjust accordingly.
oh and pics go a long way too. please provide if you want feedback.
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@Packerpower
I also run a couple 600’s and 24 to 30 in to start. ( Early veg )
I’ll gradually lower them to 18 in after the plants get to 12 - 14 in.
Think mine are 300 w at the lowest setting.
Also using 2 8 in xxxl vented hoods.
As the plants get a bit bigger then I’ll up the light output setting but leave the height the same.
Also. What are your temps and humidity ?
And yes. Pics would help as said above 
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Like Oldguy mentioned type of hood will change throw of light some. But that 2-3’ range is usually pretty basic rule of thumb.
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