If you shot your video in REC709, then you have to use impulz LUTZ for REC 709 ie. From the generic REC 709 impulz luts folder. I advise you to use the ones labelled FC. If you are using Davinci Resolve, you have to create 2 nodes and apply the lut on the 2nd node and adjust the luminance on the first node to get the image well exposed. But please, make sure you do your white balance and primary correction before doing all of this.
If you still have problems, send me a still of your footage on email@example.com and I will create a graded LUT for you to use on your footage and a power grade for you to use and see how I did it.
I hope this helps.