Can u use less of a better quality live rock?

[ecoman]

I noticed alot of the live rock at my lfs is pretty pourous. Does this make it better then the more solid rock? Or can I get away with using less weight of the pourous type? The more pourous it is, the less it weighs and bigger it is... and the more places for things to hide

 

[ktsdad]

The purpose of using pourous rock is so you have more surface area for the good stuff to live on.
The actual weight is just a measuring device. Lighter, more pourous rock would make for a better bio-filter than the same amount (lbs) of heavier, more solid rocks.
Good Luck!

 

[ecoman]

OK, so maybe I could get away with using like 75lbs of the pourous rock in my 75 gallon tank. Think that will pretty much equal the useage of using 2lbs per gallon with not-so-pourous rock?

 

[ophiura]

You have to look at this from different angles. It depends what you are expecting it to do.
IMO, in terms of the overall biological capacity of a tank - I would say that we keep plenty of LR surface either way if you are keeping a reef tank or fish only with smaller fish. If you are keeping a predator tank, I would not even consider it without bioballs, personally, or more rock and a good skimmer.
But in terms of reduction of nitrate, well, that could be an issue with less rock (as it is with a shallow sand bed). In terms of keeping animals that feed on surface of LR (such as Fromia or Linckia stars) more rock is still needed.
In terms of structure/habitat well its clear there. For a fish, 5 pounds of rock with holes and good ability to stack would be far better than a big 10lb rock without any place to hide.
So there are lots of considerations, IMO. Porous rock is definitely desirable, but it might not necessarily equate to more of the more dense rock.

 

[dogstar]

IMO there are NO good reasons to use heavy, dense, solid rock. Unless you just like the looks of it . Even for base rock its just takeing up water volume.

 

[ophiura]

I would definitely agree that there is little purpose in solid dense rock....just because it is more porous, does not mean less is necessarily just as good. I should have made that clear. I guess my point is more along the lines of if 1lb per gal may be enough for "filtration" but is not enough for some of the other reasons we use LR.