Lava rock for grill as filter material

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cgthebeast

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Wanting to add some rubble rock to my sump and I'm big fan of lava rock for its porous quality. Can the grill version safe for reef tanks?
 
I have heard that it leeches heavy metals into your water. I`ve seen a few post over the years about it here on the site.
 
I've heard mixed reviews. Although I'll be the first to say that I currently have a whole bag from the hardware store in my sump. It's been in there for over a year now and my tank is doing very well.

When I was researching I found both good and bad reviews but no real evidence. I don't know much about the grilling lava rock but I have landscaping lava rock if that's any different.

The only thing I did was rinse and removed the darker blackish pieces. I feel like it's kind of a gamble still even though I use it just because it's one of those things where no one has solid evidence. Even though I have it in my sump and have for just over a year that's not to say something won't leech out eventually.


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I can understand that, does the vinagear treatment help with these though, like does it foam or anything?
 
I've heard mixed reviews. Although I'll be the first to say that I currently have a whole bag from the hardware store in my sump. It's been in there for over a year now and my tank is doing very well.

When I was researching I found both good and bad reviews but no real evidence. I don't know much about the grilling lava rock but I have landscaping lava rock if that's any different.

The only thing I did was rinse and removed the darker blackish pieces. I feel like it's kind of a gamble still even though I use it just because it's one of those things where no one has solid evidence. Even though I have it in my sump and have for just over a year that's not to say something won't leech out eventually.


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I'd be interested in any links you came across to see what work has been done.

I'm guessing by lava rock this is volcanic rock with the holes in it?

On a quick look it looked to me that this should contain more lighter elements in the holes (silica, calcite, etc). However I do have vague recollections of pyrite (iron sulphides) being seen on field trips.

One thought would be is that if there is any secondary mobilisation of arsenic, copper or sulphur then these porous rocks (assuming I have the right ones :) ) could easily end up with mineral deposits not in the original rock formation.

So one quarry might be fine, another quarry might show this. Some guesses pre-coffee :)
 
I'd be interested in any links you came across to see what work has been done.


That was my problem when looking for information..I couldn't find any legit testing or information for lava rock usage in our tanks.

It was all speculation from people who haven't tried it because of what they heard. Or from people like me who have tried it and say it's ok. I remember one of the main points was something you mentioned that it may come from places where it could have been exposed to various other things which may or may not effect our tanks.


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No worries, was just curious as I saw this in passing.

I'm not even sure vinegar treatment would help. The theory makes sense but not sure practically as it is such a weak acid.
 
I have used the decorative lava rock for ages. I have it in my sump mixed with Matrix and have used it for 2 years now. The only thing I have ever heard is some types may leach phosphate. I haven't noticed anything, but I did cur/cycle it for about 2 months before using it.


NOW, I did have some large decorative lava rock pieces in my tank which I removed when battling my algae war, and I do suspect they were possibly leaching phosphate in the tank because the levels have dropped since then, but I did multiple things so it is far from conclusive scientific evidence...LOL


So in my experience the ~2" decorative lava rock has been ok
the big decorative pieces sold for tanks may have been a problem.
make of it what you will.


In freshwater they are great.


and isn't the vinegar test to detect for limestone or other calcareous rock?
 
Good question. Curious myself.

I guess the theory may be if there is no reaction from using vinegar then in a stable SW tank there should be no issues with heavy metal leaching?

Other minerals non-reactive to vinegar would be assumed to be stable.

If this is wrong just let us know. I don't have a SW tank so this is just a geology interest.

Phosphate can be mobile. I'm not sure how much. For the work I do phosphate has been remobilised through the rocks, possibly just with a bit of rainwater.
 
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