Hey
Flynn!
Sure you can; I think GARF's basic recipe is simply OS and cement. Conventional cement wisdom says that adding some sand to the mix makes a stronger finished product, but there is nothing wrong with only using OS to make MLR. You might hear some folks claim that it adds phosphates, that they've tested it and found phosphates, but if there are phosphates (I have never found evidence of this myself), it will be in a finite amount and very quickly consumed by opportunistic organisms. Same with silica sand - only so much goes in, only so much will be "usable" and what is usable will be quickly consumed...
Great job,
Impur! Although that sucks about the branching piece.
Did you notice a difference in overall strength with leaving it to cure longer?
ANd try to find yourself a bigger kuring bin, dude! No wonder it is taking you forever to kure rocks! With that volume of water, you'd need to do almost bi-hourly water changes at the beginning to make any headway, and I'm sure you aren't doing that - I know I wouldn't do that!
I did some tests when I kured out the 3 rocks I made for my 'Cube. Two were started in water, in separate 5g buckets, and for the first 3 days, it took less than 6 hours for my single rock to bring the pH up to 14. And once it is up to 14, I don't think much happens kuring-wise, but I'm not a chemist, so I don't know...
--------------------------------------------------------
And folks, go easy on the "Porosity". The more porous your rock is, the more likely it is to turn to gravel in your SW system. Cement is protected from chemical attack, in part, by its' denseness. That is why things like micro-silica and fly ash are used in cement - to make denser cement. When we make really porous cement, we open the cement up to chemical attack and make it more likely to completely fail.
I had a RC member (name withheld for privacy) send me a few samples of rock he had been making. I hope he will forgive me for using him as an example.
He made really, really porous rock. The problem was that it simply was falling apart, especially the test piece he had put into his system. He wanted to see what my thoughts on it were so he shipped me a few pieces. Well, I think (in part) he used to high of a ratio of CC, resulting in too porous of a mix without enough "glue". There simply wasn't enough cement to hold it all together.
This is one piece he sent; I think this might have been the piece in his tank as it has what appear to be green algae stains on it.
This is a really dark and bad video of me breaking up one of his pieces with my fingers:
I'm not really sure where the craze for "sieve rock" came from, but it isn't necessary and will often lead to failed rock.
Some might say "well, won't it work better if it is more porous?"
I don't know. I can't find any research on LR as a housing for bacteria verses porosity. But I can find a LOT of articles that make me think that you can actually have problems with rock that can house a ton of bacteria.
http://www.google.com/search?hl=en&safe=off&rls=GGLD,GGLD:2006-24,GGLD:en&q=Allelopathy+bacteria
Allelopathy is something we all know of because corals use it. Bacteria also uses it. A colony that is encroached upon by another colony may dump chemicals into the system as a way to warn the other bacteria off or to even kill it outright. In a system where you have nitrate and nitrite consuming bacteria, what do you think their main chemical weapons would be?
http://www.google.com/search?hl=en&...cd=1&q=Allelopathy+bacteria+nitrates&spell=1
For more information on Cement Chemical Attack:
http://www.sustainableconcrete.org.uk/main.asp?page=195
http://books.google.com/books?id=1B...hl=en&sa=X&oi=book_result&resnum=10&ct=result
The moral of this story is that we don't need to make pumice for MLR to work like a champ in our tanks. We've all seen real LR, and how "porous" it is (or isn't), and we know that
it works. If it isn't broke, don't fix it...
Hope this helps a bit.
