Anyone out there still use Onyx Sand?

Ghostie

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Mar 3, 2009
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Posted this in TPT forum, but no answers...
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
 

BellinghamFish

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Jan 26, 2013
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Are you going to use a ph meter? I've never used the sand but any change in kh will effect your ph meters settings
 

Ghostie

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Hello again! I wasn't planning to, do you think it would make it easier to monitor and control?
 

BellinghamFish

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I think its so close its down to personal preference, are you going to keep checking your tanks kh to keep your ph settings at the same co2 levels. I think this question is over my head I've never used a ph controller.
 

Ghostie

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I would rather no have to keep setting up co2 due to changing kh. Now that the aquarium is set up, I can monitor the kh for a few weeks and see how stable it is.
 

Ghostie

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The Onyx sand may be problematic. The water here come out of the tap at around ~1.5 kH, and I am getting 4kH 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. What do you guys think?
 

Ghostie

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After 2 more days I now have 5 dKH. 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 chaning to another substrate?
 

Tom Barr

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Black flourite sand looks better and has no such issues.
 

Ghostie

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Mar 3, 2009
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Thanks Tom, I may change over to Flourite Black sand. I am just a little worried about disturbing the mineralized soil bottom layer.

Right now the Onyx adds ~1 kh a day, so by the end of the week it is 10dKH!! The tap water here in NYC starts at 1kh! I wish I had just started with the right substrate...