Problems with bud density on 2nd grow...please help!

This is my 2nd grow. My first grow I got a great yield. Almost 1.75 lbs with 1 1000 watt hps. They came out very fluffy the first time tho. I attributed this to high temps in excess of 90-95 degrees.

Now my 2nd harvest is just coming in. I bought an AC and have kept the temps in the 70-75 range. The buds are denser than last time but still a little airy. I'm trying to fine tune everything for better results each time.

The only things I can think of that might have caused this is a very minor light leak between weeks 4-6 of flower.
Might windows are blacked out with a tarp taped over them with duck tape and for a short period of time the tape became loose and leaked a very small amount into my room.

The he other possibility is that I dried them too quick. They hung for only 3 days in 40 RH and they felt crunchy so I jarred them and the moisture came back.

Which of these is more likely to make the buds light & airy?

na man. some buds are loose the others are very dence tight hard. I know because I fuck around with 50 different kinds in one grow. running the same temp every room. one will fall off the stem other is like a rock. cold will not help you can run it 70f chances are the buds will be the same. next time get a different kind of plant. and rem just because a bud does not have solid texture does not mean the smoke will not be good. one think I have learned you really cant go by looks. I seen buds look solid so much crystal very strong smelling. sexy looking. the other loos like poop. no shite. loose buds. bug major yield. every body asked for the one that looked like poop even when it was the same value donation .as the better looking stuff. after they smoked both . so idk cant go by looks all the time, any ways. im sure your stuff is strong good. don't let any body bash it. some is like that.

What kindd said is exactly right. Get clones of a friends plant with rock hard buds and grow them side by side and see. Strain makes most of the difference in hardness. Also you can cure loose buds and make them nice and hard...

Decent link
https://www.rollitup.org/newbie-central/459698-cause-fluffy-buds.html

IMO- Look into a bud hardener supplement. "Gravity" is a good one

I have a strain that supposed to be dense. It's an OG pheno that I picked up from POG, a reputable clone nursery in the LA area.
I used avalanche flower hardener the last 3 weeks of flower. So I'm pretty sure it's either the drying process or the minor light leaks.

Theyve only been in jars for about 5 days will they get harder if I keep them in there longer ?

Isnt Gravity no suitable for non-ornamental crops? I thought they stopped selling it.

Anyway, the most common and probable cause is lack of light. 1000w should cover up to a 5'x5' area. The light should be at a distance that covers that area. Too close and you lose on the perimeter as well as potentially running into radiant heat issues. Too far and you lose penetration to everything but the very top.

I had a disappointing run with C99. I had wall to wall canopy which shaded everything below. The next run, I pulled large fan leaves off throughout the plants life. Every time I tended to them Id end up with about a handful from each plant. The results were obvious and much improved. The light was penetrating all the way to the floor and every bud site was exposed to direct light. The improved air circulation helped prevent mold, which took a few of the biggest colas from my first run.

The best part was that I had ZERO "popcorn". Every bud was dense and fully developed. I was almost bummed I had nothing for the hash pile.

Might look into defoliation if light penetration could be an issue.