# Anyone out there still use Onyx Sand?



## Ghostie (Mar 28, 2009)

Anyone out there still use Onyx Sand? I am setting up a 40 gallon with Onyx sand used over mineralized soil. I will be injecting co2, and the water here in NYC is acidic(I think it comes out of the tap at 6.8.) I guess I am worried that the buffering ability of Onyx will make setting the correct target co2 a pain. Should I be worried? 

Thanks!
Rafael


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## Ghostie (Mar 28, 2009)

So I went ahead and set up the 40 gallon last week with the Onyx sand. The water here come out of the tap at around ~1.5 kH, and I am getting 5kH from the aquarium right now(I just changed 50% of the water or Sunday.) It may make it hard to keep a target and steady co2 concentration as the kH will always be drifting up. 

I am having a hard time reading the API ph test kit it could be 6.6-6.8. I suppose if I do a weekly 50% water change, it won't be too much of a problem. What do you guys think? Should I think about changing to another substrate, or wait to see how the plants do after several weeks?


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## owens81jw (Feb 7, 2009)

What kind of plants you trying to grow ?


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## hedge_fund (Jan 1, 2006)

Go to the NEW YORK section on here and ask what PH people are getting...there are tons of NYC people there.


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## Ghostie (Mar 28, 2009)

So it seems the Onyx sand has raising the kh one degree per day. It end up being 10 kh at the end of the week before a big water change! I think I will have to move to another substrate...

Sent from my Nexus 4 using Tapatalk 4 Beta


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## Monster Fish (Mar 15, 2011)

Ghostie said:


> So it seems the Onyx sand has raising the kh one degree per day. It end up being 10 kh at the end of the week before a big water change! I think I will have to move to another substrate...
> 
> Sent from my Nexus 4 using Tapatalk 4 Beta


Geez. My suggestion to you is to use either Flourite Black or Black sand if you like the dark look of the substrate. Blasting sand is also a cheap alternative if you want that.

Quote from Seachem's website:


> Onyx Sand™ is a specially fracted, stable porous clay gravel for the natural planted aquarium. Its appearance is best suited to planted aquaria, but may be used in any aquarium environment. *Being carbonate rich, Onyx Sand™ provides an advantage to any plants able to utilize bicarbonates.* Although ideally suited to planted aquaria, it may be used in any aquarium environment. Onyx Sand™ is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels. Gravel modifiers such as laterite are not necessary. Onyx Sand™ is not chemically coated or treated *and will not alter the pH of the water*.


The stuff in bold should interest you.


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## Diana (Jan 14, 2010)

I do not know what sort of chemistry the Onyx Sand people are quoting. Raising carbonates almost always raises the pH. 

Use this tank for hard water fish. Add some minerals if the GH is too low. 
Do not keep fighting the Onyx sand to try to make it into a soft water tank.


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## Steve001 (Feb 26, 2011)

another thing about this


> *Being carbonate rich, Onyx Sand™ provides an advantage to any plants able to utilize bicarbonates.*


 All aquatic plants can use bicarbonates that part is true, but what this isn't telling anyone is utilizing bicarbonates is energy intensive creating a net lose of energy and in the long run your plants will suffer. In short it takes more energy for plants to break the chemical bonds in bicarbonates than they get from it


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## Ghostie (Mar 28, 2009)

Diana: It is also raising the GH about the same rate as the Kh. It wasn't really planned as a hard water tank, I wanted to move my fish from my old 20 gallon to this new one!


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