marine safe rock?

[Reef Puffer]

i found this rock... and there is a bunch more available. it looks like dead coral but i doubt it. it really doesnt look like lava rock, way porous and almost soft. have boiled it and cleaned it the best i can. whats the chance its marine safe. was thinking it would make a great base rock. its free and more than what i need is available.

[eli@fijireefrock.com]

i think its land based calcified rock, probably contains some metals close to tufa rock.it would help if you could get the name its sold as.

[Myka]

Stick it in a bucket of saltwater for a few days...see if anything rusts or reacts oddly? If you pour vinegar on it and it fizzes at least you would know there is significant calcium carbonate base. Hard to say if you don't know the source though. Not sure I would use it myself.

[Reef Puffer]

there is some weird mineral build up by a local lake and i find this stuff on occasion just lying on the beach. im assuming now its a sort of tufa rock(ty elias). im sure it is "growing" locally. it looks like really nice rock. very porous and like i said FREE. seems to bubble quite a bit with vinegar. so the way i see it.... it could b safe and at the same time good for my water great on my bank account and eventually a great live rock, or on the other hand one bad trace mineral and can b the death of my entire system.... Hmmmmm... thats what i thought. how many would take the chance?? fortunately my tank is cycling tho and maybe i can just b cautious with the first livestock? maybe just put it back in the garden? Grrrrr idk? o well thanks alot guys, still undecided whether to gamble or not tho.

[MuddyWaters]

I would proceed with caution. When I started Reef aquarium last year I put a base layer of Tufa rock (from LFS), then Live rock for remainder. I had horrible hair algae issues for months until I finally found a couple of websites that said these kind of issues are often caused by Tufa. In desperation I pulled whole system apart, threw out the tufa and replaces with proper live rock; haven't had any hair algae for months now. Not sure if it is caused by the chem makeup of the Tufa or just how porous and how much detritus it can hold. Your rocks, while not really Tufa, may also cause issues, especially if it is really porous; I would try a small amount at first.

bucket of salt water for a week and then put a cleaner shrimp in it if it lives a week them it is likely OK but no guaranty on that because it could take a while for a reaction to happen.
Bill

[Reef Puffer]

thanks guys!

[monocus]

could be lace rock(if it's heavy) or pumice-the froth from a volcano(if it's light).remember almost all of b.c. use to be ocean floor at one time.take it to a local high school teacher-they might be able to identify it better