Ziggy953
Aquarium Advice Addict
Here is why I say sand. The ocean bottom is sand. Sand is a natural filter as it houses beneficial bacteria that will convert ammonia to nitrite and then to nitrate, thus filtering your water. I say 1.5-2lbs of LR per gallon because with that amount of rock you will have more surface area for additional bacteria colonies to grow and filter your water.
I have so much rock in my system because I have a total water volume of about 240g of water. I have a 55g frag system plumbed into my display and sumps so I have additional LR in my sump to help filter the additional water volume. I have a large refugium (20g) to further filter my water. I also use a large and powerful skimmer to keep the DOCs in check. I do not use chemical or mechanical filtration unless a situation calls for it. Since my recent tank disaster I have used GAC a couple of times simply because I stirred up a lot of nasty stuff.
I would suggest using sugar fine or aragonite or a mix of the two for your substrate. Quartz or Crushed Coral are not the best options especially if you are planning on having a reef tank. The particles are large enough that they will trap detritus and can lead to higher nitrates and with that algae outbreaks.
