Quote:
Originally Posted by kien
I'm probably somewhere at around 1/4 a pound per gallon of rock 
Also, it really isn't how much rock you have in weight. Some rocks can be ridiculously porous and light, which is more important, rather than a giant bolder that weights 3 times as much. |
+1 That's my understanding of that as well. You could put large non-pourous boulders and you wouldn't acheive very much filtration. When I go diving I study the reefs really close, and I've found the base of the reefs are very dense and then they become pourous as you ascend higher up the reef wall.
My Dad uses a ton of Rock but there are many spaces for caves, he went with lots of flat pieces rather than large boulders, his tank is over 10 years old...I've had better luck with pourous light rock myself.