# Anyone actually use lava rock as bio media?



## duckweed420 (May 24, 2016)

I'm seeing a lot of mixed reviews out there. Some people say it's garbage compared to ceramic media, while others say it works like a charm. Some say it gets clogged up quickly, while others say they never had that problem. I haven't seen any conclusive proof one way or the other, and it seems most of the answers I've seen are based completely on assumptions or rumors. Has anyone here actually used it? How did it work out and how much of it did you use?

Also, if I wanted to do an experiment to compare different bio medias, what would be the best method? I'm thinking of setting up a 5 gal bucket with plenty of cycled media in the filter and removing a little bit at a time until it can no longer handle 2ppm or so of ammonia in 24 hours. Then measure how much media is left. It won't be a conclusive test as far as different water volumes and flow rates, but at least it will allow me to get an idea of how two different medias compare.


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## grizzly_a (Sep 9, 2014)

lava rock or pumice? What size? 3/4' minus?

Lava rock and pumice were available well before the ceramic rings, sintered glass, and other options were available. It's very porous by nature and will likely work, it just depends on how big, how much, and how porous it is.

Sounds like you have a great experiment to undertake. I would think you'd want to start will all the biomedia in the same container and cycle it so you know it's capacity and then separate into types and do your experiment.


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## duckweed420 (May 24, 2016)

Lava rock seems to be more common and commonly available. I haven't heard too much about pumice. From what I understand, it's best to crush it up to be about pea gravel size or so to get more surface area. But I've also heard of people using normal barbecue lava rock without crushing it at all.

If I end up doing the experiment (which I plan on since I already have all the equipment), it'll probably take a few months, but shouldn't be too complicated as long as I keep up with it. I wonder if anyone's done experiments like this before though. Surely the rules of thumb on how much media to use came from somewhere...


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## AbbeysDad (Apr 13, 2016)

I haven't used what is commonly referred to as lava rock. I have used Seachem's Matrix and DeNitrate which is a type of lava rock (pumice stone). Frankly, I think most of what is marketed as bio-media is just more costly hype. After many years, I've come around to thinking that the very best material platform for beneficial biology is the simple bio-sponge. You'll find many large fish rooms will simply use air driven sponge filters. I use bio-sponge material in my AC70 HOB's - coarse to trap detritus (and house decomp bacteria), then finer for beneficial bacteria and finally a bit of polyester floss for polish. I feel it works every bit as good or better than any of the materials marketed as bio-media.


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## Immortal1 (Feb 18, 2015)

duckweed420 said:


> Lava rock seems to be more common and commonly available. I haven't heard too much about pumice. From what I understand, it's best to crush it up to be about pea gravel size or so to get more surface area. But I've also heard of people using normal barbecue lava rock without crushing it at all.
> 
> If I end up doing the experiment (which I plan on since I already have all the equipment), it'll probably take a few months, but shouldn't be too complicated as long as I keep up with it. I wonder if anyone's done experiments like this before though. Surely the rules of thumb on how much media to use came from somewhere...


I have not gotten around to testing lava rock but I do have a lot of testing information that may be of some use to you. Look for the Matrix without Seachem thread in the equipment forum. Lot of pages of semi useless information but, there may be something of interest to you there regarding how I have been testing things.


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## duckweed420 (May 24, 2016)

Immortal1 said:


> I have not gotten around to testing lava rock but I do have a lot of testing information that may be of some use to you. Look for the Matrix without Seachem thread in the equipment forum. Lot of pages of semi useless information but, there may be something of interest to you there regarding how I have been testing things.


I read through most of it and that was pretty fascinating, especially the bare tank. Actually I think you've dissuaded me from doing any testing lol. If a bare tank can handle that much ammonia, then what's the point? I think it'd still be interesting to see how different media stack up to each other, but it'd be hard to make sure the bacteria is growing in the media and not everywhere else. Maybe I'll think of something.

Hey, at least my original question is answered though. If a bare filter is sufficient, then adding some lava rock will be more than enough.


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## Nordic (Nov 11, 2003)

The more surface area you have, the thinner the icky bio film layer over everything is.


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## chappy6107 (Aug 2, 2016)

I use this in one filter exclusively:
[Ebay Link Removed] Soil Mix Cactus Succulent Bonsai 3 5 Gallons | eBay[/url]

My parameters are always good


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## secuono (Nov 19, 2009)

I have lava rock in both of my heavily planted tanks. The foam is the only thing that clogs and takes time to rinse. The lava rock cleans super easily. Also have lava rock in my pond filters and pond's bog.


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## Immortal1 (Feb 18, 2015)

Nordic said:


> The more surface area you have, the thinner the icky bio film layer over everything is.


This is an interesting statement - at one point lonestarbandit and I thought the Matrix / Pumice would be fully slimed but they weren't.
When I took all the bio media out, the remaining plastic areas seemed to have a much more noticeable slime layer on them. I think @Nordic hit the nail on the head with the above statement.


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## chappy6107 (Aug 2, 2016)

for my post #8 I guess links are not allowed.

it is pumice soil mix for cactus


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## Immortal1 (Feb 18, 2015)

chappy6107 said:


> I use this in one filter exclusively:
> [Ebay Link Removed] Soil Mix Cactus Succulent Bonsai 3 5 Gallons | eBay[/url]
> 
> My parameters are always good


Pretty funny - looked on the "Bay" for the above product. It is $7.25 for 3.5 gallons.
Seachem Matrix, also on the "Bay" is $35.99 for 4 liters which equals 0.908 gallons.

Now, if you do the math that works out to;
$0.02 / ounce for Soil Mix Cactus Succulent Bonsai
$0.31 / ounce for Seachem Matrix

hmmmmmmm


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## chappy6107 (Aug 2, 2016)

Immortal1 said:


> Pretty funny - looked on the "Bay" for the above product. It is $7.25 for 3.5 gallons.
> Seachem Matrix, also on the "Bay" is $35.99 for 4 liters which equals 0.908 gallons.


This is exactly why I bought the regular ole cactus soil pumice.


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## AbbeysDad (Apr 13, 2016)

I tried for over a year to culture anaerobic bacteria to convert nitrates into nitrogen gas using large quantities of Seachem Matrix, DeNitrate and Stability. Epic Fail.


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## Immortal1 (Feb 18, 2015)

AbbeysDad said:


> I tried for over a year to culture anaerobic bacteria to convert nitrates into nitrogen gas using large quantities of Seachem Matrix, DeNitrate and Stability. Epic Fail.


Interesting. Knowing this, I feel a little better not trying to accurately test Nitrate levels in the Matrix without Seachem thread.


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## Maryland Guppy (Dec 6, 2014)

duckweed420 said:


> Has anyone here actually used it? How did it work out and how much of it did you use?


I have been using it for 2 years in two tanks in canister filters.
Works great, not slimy, when cleaning filter I remove the lava rock and just slosh it around in tank water from a water change. No other cleaning than this was done. Since tanks were cycled in the beginning I have never had any mini-cycles etc... I remove everything from the canister quarterly rinse in tank water and reassemble. The rock is never slimy but the PVC housing sure is.

I use 1 liter in each DIY canister. If chunks are too big I break with a hammer. Home Depot sells this in a 22 pound bag as a flower bed mulch replacement. It costs just under $4 I still have some left even after my wife used it to scape in her shrimp tanks. I also crazy glue ferns and mosses to it all the time.


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## Immortal1 (Feb 18, 2015)

So, it can have multiple uses - in the canister (smashed with a hammer) and in the tank with the plants. Can't think if a better product


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## Maryland Guppy (Dec 6, 2014)

Immortal1 said:


> So, it can have multiple uses - in the canister (smashed with a hammer) and in the tank with the plants. Can't think if a better product


It is a multi-purpose product for sure! :laugh2:

Also I have no complaints with using it.


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