I think 1 1/2 to 2 lbs is a good thing. ut keep in mind, you want rock that is porous and light if possible. Just pounds don't mean a thing IMO
. Are you going with a reef setup? Otherwise, you may not need that much rock. What kinda substrate u using?
My tank is nearly at 2 lbs per. Stacked up on the rear glass even, yet plenty of swim thru and hiding space too. My open water is plentiful out front. They can dart back and forth easily.
With that much rock, you get more natural filtration going on. Heck, I can keep my nitrates at 5 or less without even using my skimmer for 3 weeks (or more) at a time.
Check out Marshall Island rock too. Keep in mind, u can also use dry base rock now and be real selective about your choices. Light and airy/porous.