Talk me out of basalt rocks?

[Tob]

I posted this in DIY because I'm not sure how much more DIY it can get than harvesting my own rocks...

Getting ready to add more rock to my tank.

I live in southern Idaho and can walk out my back door to get real basalt rock. Some has lichens and creepy crawlies, obviously I plan on cleaning it well based on the articles I've read. And I'll also keep an eye on anything that deteriorates while cleaning/before I put it in the tank to make sure this isn't just a disaster. I've read what I can about doing this and it seems like people aren't a fan of using basalt they can buy because of manufacturing and contaminants but this is 100% raw volcanic basalt. So as far as I can tell, this is what I've got...

Pros:
-Save money
-Porous
-Epoxy for the joints will blend in better than white rock
-Non-marine rock, no hitch hikers
-It'll be a good experiment

Cons:
- ???

For context: I bought a 78 gal tank that's been established for a year. Getting ready to redo the whole thing but will be keeping the live rock I already have while I add new rock in stages. I want to build a negative space aquascape in two parts with new rock and eventually removing the live rock that's in there now. I've seen some people have success with basalt and I'm wondering what the general consensus is if I ask directly.

Thanks!

 

[Shooter6]

I posted this in DIY because I'm not sure how much more DIY it can get than harvesting my own rocks...

Getting ready to add more rock to my tank.

I live in southern Idaho and can walk out my back door to get real basalt rock. Some has lichens and creepy crawlies, obviously I plan on cleaning it well based on the articles I've read. And I'll also keep an eye on anything that deteriorates while cleaning/before I put it in the tank to make sure this isn't just a disaster. I've read what I can about doing this and it seems like people aren't a fan of using basalt they can buy because of manufacturing and contaminants but this is 100% raw volcanic basalt. So as far as I can tell, this is what I've got...

Pros:
-Save money
-Porous
-Epoxy for the joints will blend in better than white rock
-Non-marine rock, no hitch hikers
-It'll be a good experiment

Cons:
- ???

For context: I bought a 78 gal tank that's been established for a year. Getting ready to redo the whole thing but will be keeping the live rock I already have while I add new rock in stages. I want to build a negative space aquascape in two parts with new rock and eventually removing the live rock that's in there now. I've seen some people have success with basalt and I'm wondering what the general consensus is if I ask directly.

Thanks!

What's the rock made of

 

[miltonkl]

How easy would it be to break and scape with if you're trying to build an NSA? Do you like the look of it compared to standard reef saver stuff? I'd go out and break some up, clean it off, and pop it in a small experimental tank before introducing it to your display.

 

[Tob]

What's the rock made of

It's volcanic basalt

 

[Tob]

How easy would it be to break and scape with if you're trying to build an NSA? Do you like the look of it compared to standard reef saver stuff? I'd go out and break some up, clean it off, and pop it in a small experimental tank before introducing it to your display.

The biggest priority for me is saving some money. I have acres of it, I'm sure I could find enough pieces that I wouldn't need to break any. I think I will just try it and see how it goes!

 

[Shooter6]

It's volcanic basalt

Be super careful with volcanic rock, as it can contain high silicate, iron, lead, copper ect ect. Probably would be safe in a fish only, but In a tank with invers and corals it can cause huge issues.

 

[oreo54]

The biggest priority for me is saving some money. I have acres of it, I'm sure I could find enough pieces that I wouldn't need to break any. I think I will just try it and see how it goes!

Related discussion..

Use Of Volcanic Rock In Our Tanks ?

We used "volcanic live sand" from Hawaii in our 29g cube. It was cycled in 3-4 days. I've never heard of anyone using volcanic rock, as their rockscape and later to build as live bacteria rock like we use from reefs. I've used it as bacteria media in ponds for many years with great success...

www.reef2reef.com

Build Thread - 220 Gallon Volcanic Lava Rock Reef Tank Build

Fantastic build! Love the tech, going to embark on the UPS backup solution shortly. And welded Aluminum stand to boot!

www.reef2reef.com

YMMV

 

[jcolliii]

I take it you're near craters of the moon or the Columbia river? Basalt is lower in silica for an igneous rock, but it's still near 50%, but silica is largely insoluble at surface pressures and temperatures. If you are thinking about the glassier pumice or super vesicular (lots of holes) stuff, I would say that should be fine - the glassy texture means the minerals have not had a chance to grow because they froze really quickly. If you are talking about the more typical massive basalt where you might be able to see some very small crystals with your naked eye, I would advise against using that for several reasons.

1. It's *super* hard. It will be very difficult to break up, and the shapes that will result will be blocky due to the cleavages of the main minerals also being quite blocky.

2. It has *very* low porosity - so very little internal space for bacterial colonization (again, not the case if you get the scoriatic or really frothy highly vesicular or bubbly looking stuff).

3. It contains a relatively high percentage of magnesium and iron, and the minerals are larger. The main minerals in basalt are feldspars and pyroxenes. Feldspars will break down over longer timescales [I have personally seen feldspars hydrolize out of igneous rocks (chemically break down in the presence of water) measurably (several mm) over month when conditions are favorable for that], but they break down largely to aluminosilicates (clays) and sodium, calcium, and potassium ions. Pyroxenes do contain quite a bit of iron, and will also break down into aluminosilicates. I am not sure if you see it in that area or not, but some hotspot basalts (if you're near COtM, this could be the case as Yellowstone is a hotspot volcano, meaning a very deep magma source) contain olivine. Olivine is a beautiful green to black mineral with glassy crystals that if gem quality go by the name peridot. Olivine is a rather bizarre igneous mineral because the irons are ionically bonded to the silicas, and because of that, they can be released quite rapidly. There can be some accessory mineral that contain titanium, and other iron bearing ones as well. Aluminosilicates from feldspar breakdown tend to be very stable under typical conditions on land, and I would imagine in seawater as well, but I don't know their solubility offhand.

4. Basalt is heavy. If you use a lot of it, it will add a lot of weight to your tank. Your water's density, for example is around 1.02 g per cubic cm. Basalt is around 3g per cm^3. So if you use a lot, it can add substantial weight.

A lot to consider. I would not use the non-glassy, more massive stuff, and I am a geologist. The glassy, vesicular stuff that you see in pet stores is probably okay as the glassy nature would make it much more difficult to break down. If that is the kind of stuff you have (pics would help), then probably okay. As an aside - I would never use crushed basalt for a substrate (black sand) as low pH conditions that can occur in the sediment due to bacteria breaking down organics. will accelerate chemical weathering and potentially release more of those metallic cations.

 

[oreo54]

Not going to comment on it one way or another.. and oceans certainly aren't a closed or semi-closed (water changes) system but just found some interesting "things" related to iron.

Artificial Reefs: What works and what doesn’t

Artificial reefs can benefit marine life or cause more harm then good, it all depends on how they are built

newheavenreefconservation.org

Probably the most exciting method of artificial reef construction is the use of mineral accretion devices, or electrified artificial reefs (traditionally known as Biorock™). These start off just like our modular metal structures made of rebar, but once in the water low voltage electricity is passed through the structure. This creates an effect known as electrolysis, which provides cathodic protection to the structure (prevents it from rusting or corroding), and furthermore causes minerals from the sea water to precipitate out and collect on the metal. This action creates a beneficial environment for the growth of corals and other calcium carbonate secreting organisms, which tend to grow much faster on these structures (up tp 3-5 times) and survive better through disturbances such as temperature induced bleaching

Seafloor hot springs a significant source of iron in the oceans

A two-month voyage tracking a deep current flowing from one of the most active underwater volcanoes proves that iron released from hydrothermal vents travels thousands of miles, providing a...

www.washington.edu

Metals, especially iron, are crucial to the growth of phytoplankton in the oceans. In many parts of the ocean iron controls the growth of marine life even though it is only present at concentrations of parts per trillion.
Most of the iron in the ocean comes from dust blown off deserts, or from rivers that discharge into the sea. But recent research, some conducted by co-author Christopher German at Woods Hole Oceanographic Institution, hinted that iron might also be escaping from the volcanic ridge crest by exploiting some type of chemical trick to make the long-distance voyage.

Chemistry And The Aquarium: Iron In A Reef Tank

Randy discusses iron and its usage in our aquariums.

reefs.com

Magnesium

Magnesium leaching from rock? - Reef Central Online Community

Magnesium leaching from rock? The Reef Chemistry Forum

www.reefcentral.com

Benefits of Magnesium in Saltwater Aquariums

Often overlooked, magnesium plays a critical role in chemical and biological processes in an aquarist's saltwater aquarium. The magnesium content in natural saltwater is only behind that of sodium and chloride, making it a major element as opposed to a trace element. Magnesium is essential to...

bluefishaquarium.com

And fun with basalt..

Basalt – Formation, Properties, Characteristics

Learn how basalt forms from mantle magma, its mineral composition, types, and global significance in Earth’s crust and volcanic provinces.

geologyscience.com

And Olivine:

https://pubs.acs.org/doi/10.1021/acs.est.6b05942

FYI only..

 

[MaxTremors]

I wouldn’t use it for the reasons mentioned above, but also because it won’t help buffer your PH. That alone is reason enough not to use it. I’m also in southern Idaho, and there is no way I’d use the volcanic rock around where I live (treasure valley) in one of my tanks, just for aesthetic reasons.

 

[jcolliii]

Iron is a somewhat limiting element in the ocean for plankton and for algae. I lecture about some fairly unusual schemes to help mask the human induced effects of global change. One of those schemes is ocean surface fertilization. The idea is that to help absorb large masses of CO2 and sequester it away, just add some fertilizer to the surface oceans, induce a massive phytoplankton bloom (algae), and then those plankton, when they die and slowly drift to the ocean bottom along with their carbon, it is sequestered away. Of course, this notion is fairly ludicrous, as it produces oxygen minimum zones and kills anythign that might be living there, and even though the open ocean might be a desert, fish still liver there. The 'fertilizer' used in these experiments: iron.

Fun, indeed.

 

[Shooter6]

Iron is a somewhat limiting element in the ocean for plankton and for algae. I lecture about some fairly unusual schemes to help mask the human induced effects of global change. One of those schemes is ocean surface fertilization. The idea is that to help absorb large masses of CO2 and sequester it away, just add some fertilizer to the surface oceans, induce a massive phytoplankton bloom (algae), and then those plankton, when they die and slowly drift to the ocean bottom along with their carbon, it is sequestered away. Of course, this notion is fairly ludicrous, as it produces oxygen minimum zones and kills anythign that might be living there, and even though the open ocean might be a desert, fish still liver there. The 'fertilizer' used in these experiments: iron.

Fun, indeed.

That's only one of the metals that the rock can hold as well. Imagine the effects of copper, lead, chromium ect ect. The op could spend a fortune on livestock death all while trying to figure out its the rock leeching poisons the whole time.

 

[AlexG]

Contamination is always a concern with any rock being used. The only way to really know if you have an issue with contamination from a rock source like basalt would be to put it in a tank for a few weeks then send out an ICP water test to see if anything comes back at high levels. The other issue would be the pH that hold with basalt rock compared to a limestone rock.

 

[Tob]

I take it you're near craters of the moon or the Columbia river? Basalt is lower in silica for an igneous rock, but it's still near 50%, but silica is largely insoluble at surface pressures and temperatures. If you are thinking about the glassier pumice or super vesicular (lots of holes) stuff, I would say that should be fine - the glassy texture means the minerals have not had a chance to grow because they froze really quickly. If you are talking about the more typical massive basalt where you might be able to see some very small crystals with your naked eye, I would advise against using that for several reasons.

1. It's *super* hard. It will be very difficult to break up, and the shapes that will result will be blocky due to the cleavages of the main minerals also being quite blocky.

2. It has *very* low porosity - so very little internal space for bacterial colonization (again, not the case if you get the scoriatic or really frothy highly vesicular or bubbly looking stuff).

3. It contains a relatively high percentage of magnesium and iron, and the minerals are larger. The main minerals in basalt are feldspars and pyroxenes. Feldspars will break down over longer timescales [I have personally seen feldspars hydrolize out of igneous rocks (chemically break down in the presence of water) measurably (several mm) over month when conditions are favorable for that], but they break down largely to aluminosilicates (clays) and sodium, calcium, and potassium ions. Pyroxenes do contain quite a bit of iron, and will also break down into aluminosilicates. I am not sure if you see it in that area or not, but some hotspot basalts (if you're near COtM, this could be the case as Yellowstone is a hotspot volcano, meaning a very deep magma source) contain olivine. Olivine is a beautiful green to black mineral with glassy crystals that if gem quality go by the name peridot. Olivine is a rather bizarre igneous mineral because the irons are ionically bonded to the silicas, and because of that, they can be released quite rapidly. There can be some accessory mineral that contain titanium, and other iron bearing ones as well. Aluminosilicates from feldspar breakdown tend to be very stable under typical conditions on land, and I would imagine in seawater as well, but I don't know their solubility offhand.

4. Basalt is heavy. If you use a lot of it, it will add a lot of weight to your tank. Your water's density, for example is around 1.02 g per cubic cm. Basalt is around 3g per cm^3. So if you use a lot, it can add substantial weight.

A lot to consider. I would not use the non-glassy, more massive stuff, and I am a geologist. The glassy, vesicular stuff that you see in pet stores is probably okay as the glassy nature would make it much more difficult to break down. If that is the kind of stuff you have (pics would help), then probably okay. As an aside - I would never use crushed basalt for a substrate (black sand) as low pH conditions that can occur in the sediment due to bacteria breaking down organics. will accelerate chemical weathering and potentially release more of those metallic cations.

Well, dang.

I'm closer to Craters of the Moon than the Columbia River. I live a few miles south of the Snake River canyon. I haven't seen any of the glassier basalt around here except straight up obsidian which I doubt is conducive to bacteria growth haha! I know I could hop in a 4WD and go just about anywhere but it'll all be from those old shield volcanoes and the Yellowstone hotspot (though I did find some massive chunks of obsidian a few years ago in the mountains that I brought home. Luckily I was in a Jeep and didn't have to carry them!)

I really appreciate your input. I was even able to follow most of it thanks to my two whole semesters of Geology 15 years ago I didn't realize basalt is that much heavier than other options and I think that alone is worth not taking the risk for me, personally.

I really am grateful for such an informed direct answer to my question!

 

[jcolliii]

Two semesters - were you considering the major, or just interested? Awesome that you could recall that much from 15 years ago! If my students could recall what I lectured about 5 weeks ago I would be happy! J/K - my students this semester may be one of the best groups I have had in awhile.

 

[Tob]

Two semesters - were you considering the major, or just interested? Awesome that you could recall that much from 15 years ago! If my students could recall what I lectured about 5 weeks ago I would be happy! J/K - my students this semester may be one of the best groups I have had in awhile.

Yeah I was considering it but ultimately didn't go for it. It's a fascinating field though and I really enjoyed learning what I did.