LED lights, PAR, distance: Some tech help please

[Triffid]

I am running 8 3500k +660 strips at 18w each in a 2'x2' space.

In my last grow I had the lights at 850 PAR at 10", mid to late flower, and my plant got light burn quite badly.

I thought I would be able to run up to 950 PAR in the late stages, so I must be missing something.

What is most important to work with?
the distance from light to plant?
the PAR?
the Watts?
that thing I don't know but should?

Thanks for your time

 

[TorturedSoul]

Do you mean the lights burned your plants, or the lights bleached your plants?

Also, if the company is a forum advertiser, which brand/model of PAR meter are you using?

 

[Triffid]

Burnt, no bleaching that I could find, but I am not completely sure, hence asking =)

Using Hydrofarm Quantum PAR Meter.

There was some nutrient burn in the first shot, had the EC a little high. When it cam to harvest time, it was very clear that the exposed area was damaged compared to the vibrant green of everything under the canopy.

First pic is all still green, second is one month later.

A little closer

These are close up shots of when the burn started.

 

[Triffid]

And a couple of shots of the lights, I have moved the driver out of the tent to help keep the temp lower.