Clueless, we'll help you on the algea issue in your other post. To answer your questions about 2Lbs per gallon. This is a great place for you beneficial bacteria to thrive. This bacteria converts ammonia (fish waste, left over rotting food) to nitrAtes. It also provides hiding places for new additions and current critters. If you have a low bioload, you really don't need to have that much rock. You will be surprised at how much LR
you can get in there and make it look nice and uncrowded.
You can also have a little less LR
of the rock is super porous.