Lava Rock, submerged ok?

[pjsmetana]

I have a ton of lava rock in the flowerbeds in my front yard. I'm considering using some in a submerged application (Sort of a DIY canister idea, I'll only share if it works). I like recycling what I already have for ideas, instead of making waste while experimenting. I have a few concerns before progressing:

Is boiling lava rock ok for disinfecting them?

Will the lava rock effectively house BB in a fast moving water, submerged application?

Does it have a tendency to break apart over time?

Can I drill holes in the lava rock to increase surface area or will it make them too brittle?

 

[clemsonguy1125]

Ive heard of lava rock working decently on pond filters when submerged but in general, its not a great media, it clogs easily and does not have that much surface area relative to other media.

 

[nfored]

I have ran lave rocks from the begining and have them submerged.

I have like 15 - 20 lbs of lava rock 1l of matrix and .5l of bio max.

With that said its cheap and if you have enough space to use enough it will work. However I will not be using them any more, and honestly would like to start switching out the lava rock I have.

On my new tank I will use 100% matrix. The reason I don't want the rock is because you need more of it to do the same job as real bio media, so you need more space. when you can get 4l of matrix for 30 bucks or so no reason not to use it 4l should be enough for heavy stocked 200G

 

[pjsmetana]

Thanks guys. Lava Rock out.