im going to the lfs tonight to get water and possibly live rock. i am planning on getting 11-15 lbs of lr for a 20 gallon frag tank. does it matter what type of live rock i get as long as it is porous?
Not really....a matter of preference. Look for pieces that are relatively light for their size (an indication of porosity). Some you may like the size or shape of, or you may see some color coralline that you like...or even a critter or two. Most LFS don't have a great deal of selection, IMO, of "different" LR...meaning Florida vs. Pacific, Tonga branch versus regular stuff. But maybe you have a really good LFS!