Crushed Lava Rock For Filter?

[RRaquariums]

So I'm kinda doing an experiment with some crushed lava rock as a filter media.
I have heard mixed reviews on it and wanted to know if anyone here has used it and what the results where?

 

[AirFarceLive]

Well, using lava rock as a decoration is a great idea but... filter media? Seems kinda wild and so I actually tried it ona 5 gallon shrimp planted biotope and well... no change, not worth wasting time with it. Stick to good old active carbon and other recommended media, nothing fancy. 

 

[RRaquariums]

I'm not going to use it as a all in one that's for sure but I'm going to use it as a fast cycle media for when I start up a new tank.
I will throw it in on top of a new filter and it should help get the beneficial bacteria started faster as the junks I got are very pores and seem to be growing bacteria on them after just 3 days.
I will do some test on a guppy tank I'm starting up and see how it goes.

 

[coolie]

Do you mean actual volcanic rock you've collected yourself. I have done this myself, but you have to remember that there are millions of types of volcanic rock, so the results are always going to be experimental. You could see the alkalinity of the water rise for example. The other thing is to look for rocks which are not those tyoical volcanic rocks which are smooth all over but with large holes in (like cheese)  but rocks which are micro porus (under a microscope full of tiny holes). I have some of this to try. It's experimental in the same way adding rocks you've found to the tank, e.g. granite is slightly radioactive, rocks that put certain chemicals into the water etc.

 

[Blobfish]

I've wondered a few times if lava rook would act in a similar way to live rock but I suspect people will have tried it over the years and we'd know by now if it worked well.  Not that I want to put you off trying, it's an interesting experiment.

 

[RRaquariums]

The stuff I got looks just live live rock pores wise so that's why I decided to try it plus it was 4$ for a 40 pound bag of the stuff so if it dose work out I will be very pleased.

 

[KirkyArcher]

http/ecx.images-amazon.com/images/I/51hUzldVryL._SX450_.jpg Can get it from places that sell Gas barbeques £6 for 5Kg (about 10lb of the stuff for $10) possibly cheaper if you shop around

 

[coolie]

Sorry - I thought you meant volcanic rock, which is basically from lava "flows", my project involves about 1kg I brought back to the UK last month.

 

[TwoTankAmin]

Lava rock will host bacteria. So will plastic scrubbies, plastic curlers etc etc. The bacteria need a hard surface to which they attach in a bio-film with also contains other non-nitrifyiny bacteria.
 
For my money most of the pricey bio-media are a con job. Sponges work just as well. All you need is surface area for the bacteria to colonize on. But the bacteria are in no way limited to living in our filters, they are all over our tanks. There is a fair amount in the substrate (in the 1st 1/2 inch for non planted tanks and way deeper, and usually in greater numbers, in planted tanks with rooted plants). They are on the rocks and other hard surfaces of a tank, They will be anywhere out of the direct light and where the flow brings them a steady supply of what they need. The bacteria don't go out looking for dinner, it must be delivered.
 
So go ahead and use the crushed lava rock if you want. Do not make the pieces too small as you want good flow through your rock bed. But bear in mind this stuff can have sharp edges. It seems to me easier to just use a decent size gravel? I would still pick sponges though. I have them air driven, in hang on filters and even in my canisters.