Black sand for Corydoras and Plants?

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Jan 24, 2022
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I'm currently setting up a low tech 55g aquarium and I'm having trouble with the substrate. To cut to the chase, I'm looking for a black sand that won't be harsh on the cories and other bottom dwellers, but will also be a practical substrate for plants without too much extra care. I've heard that some sands can cause lacerations to cories as well as barbel erosion (I have also heard this is a myth and its actually water quality, but better safe than sorry).

I have a few bags of SeaChem Fluorite Black Sand on the way, but I've heard mixed reviews and might want to try something different. I've also heard that Black Diamond Blasting Sand works great for cories and plants when washed and used with root tabs, so thats what I'm leaning towards right now. Although I would prefer not to, I'm willing to spend a fair bit of money for nice sand as well as extra time to keep the plants healthy if the substrate is not enriched. Any ideas? should I just stick to what I ordered? What do you use? any advice is appreciated.

Thanks for the help!
I have tried the Florite Black sand and my cories did not like it, appeared to be the cause of barbel erosion . It is very dusty and requires a lot of cleaning. Plants did ok. The sand seems to be lightly magnetic and you have to be very careful not to allow any of the dust to go up your filter, though I heard that is a problem with the Black Diamond or Black Beauty blast media too. I suspect the black color of these products are due to iron minerals. I was ok with its appearance.

One sand I would like to try is Garnet Blast media. Garnets are mined and typically a darker red color. I cannot source it here but you might be able to at your location. I would suggest using the lower grade from the river and lake deposits as this will not have as angular a particle size. The once concern I have with garnets and some of the other blast media is that they are harder than the glass on the aquarium so one would have to be a bit more careful when cleaning the glass. You would have to treat the glass more like an acrylic. Garnet is also heavier so it will not go into your filter as easily but if it does it has a potential to really destroy the impeller drive assembly because it is quite hard.
I used Flourite some years ago (was foolishly persuaded that it actually benefits plants, but it does not) and within a week had to net out the poor cories; they had no barbels, and one pand even lost about a third of its lower jaw. Placed in another tank with play sand, they all recovered, though the one panda did not "regrow" its jaw, but was obviously able to eat as it lived another 7 or 8 years.

Roughness is obviously a concern, along with bacteria. I have not used or handled the garnet sand referred to above, but from what is written, I would never put cories over this. Blasting sand by its nature is rough, it is not proce3ssed to be smooth and soft like play sand and aquarium sands. Another member this week mentioned dangers from blasting sand, to himself and his aquarium. Cories are continually taking in a mouthful of the substrate and expelling it out through the delicate gills.
Flourite is a nice looking sand but I agree it’s too rough for bottom dwelling fish. I wanted a black sand for one of my Cory tanks as well. I had difficulty finding one smooth enough so I gave up and went with a natural looking sand by CaribSea.

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