Dense buds recommendations

Hi just looking to know what has everybody grown here that is nice and dense sick of getting airy buds any recommendations?

Airy buds is the result of whatever lights you are using

I’m using 600w hps in 4x4ft tent

What strains have you grown then? The 600 HPS should make better than airy buds.

I’m growing dark devils auto, triple cheese photo period blueberry Og peyote critical cookie kush and lemon Auto only one that is dense is peyote critical and lemon auto is not bad but everything else seems light and airy compared all using same lights same nutrients