lava rock

[supersam]

What would happen if I would use lava rock from a freshwater tank in my saltwater tank? well I did, and I can't get my nitrates down. I did a 18 gallon water change and I tested a week later and my nitrates were at 20. (I have a 55 gal tank) Is the lava rock the problem? Well I believe the lava rock was from a freshwater tank, I bought it used at a garage sale.

I don't over feed. I tested the water change water and it was perfect. I have an emporer 400, sand bottom 30 # live 50 #playsand.
nitrites and amonia at 0

I have 1 yellow tang
1 perc clown
1 watchmen
crabs and snails

 

[Navarre]

Lava rock doesnt work the same way liverock does. many people think they can cut corners and use a cheaper form of rock but alas its not the case.
Lava rock is not porous like liverock and thus all you get are oxygen requiring bacteria (aerobic i think.. i always get em mised up). this bacteria is highly effective at converting waste to nitrates but that is all. You need the liverock yo creat an Anaerobic environment (oxygen poor) so the bacteria here can dissovle nitrates and convert to harmless nitrogen.