Substrate for Corydoras?

[Leopardfire]

I have 4 albino cories in my 20 gallon long tank. I know cories do best in sand, so I got some black aquarium sand from petco. When I put it in, it raised the ph to over 9 and I lost half my fish. The other cories are barely alive and hardly eat or move. I am going to move them into a 5 gallon tub while I fix the ph.
What substrate should I get for the cories? I really don't want to risk getting sand again because there's a good chance it will mess with the ph. Also, pool filter sand only comes in white which would blend in with my cories and I really don't want to spend another $40+ on petstore sand only to have it fail again. Would cories be okay in black gravel? I know it can be hard on their barbels, but if it was smooth and pretty small, do you think it would work?

[ChoclateBetta]

I doudt it was the sand. What are the other decorations. Any substrate without jagged edges that are smooth.

[Leopardfire]

I know it seems unlikely that it was the sand because so many people use that brand without a problem. However, I put some in a bucket and over the course of 2 days, it raised the ph from 7.5 to 8 and I'm sure it would have gone higher if I left it longer. I rinsed out the sand and repeated the test again to make sure but the same thing happened so I'm positive it was the sand. Do you think it's possible I got a bad bag?

[ChoclateBetta]

Maybe a different brand if you want you could use planted aquarium sand but cories need soft substate without sharp areas for their barbels.

[ChoclateBetta]

http://www.theaquariumwiki.com/Cories

[Tikibirds]

Mopani wood may help. I know it lowers the PH of my water so much that I had to add coral and a bunch of shells to get the PH into the neutral region.

or you can try play sand. I got a 50 pound bag for like $7 from Toys r Us

[Leopardfire]

Mopani wood may help.

Thanks could I find this at petco or petsmart

[registereduser]

Originally Posted by Leopardfire

Thanks could I find this at petco or petsmart

I buy mine at Petco. I also use gravel that is not too rough and my cories have all their barbels.

[Leopardfire]

I also use gravel that is not too rough and my cories have all their barbels.

What kind of gravel is it? Did you get it at Petco too?
Also, do you think I should try using things like wood to lower my ph or should I just get rid of the sand altogether

[registereduser]

Originally Posted by Leopardfire

What kind of gravel is it? Did you get it at Petco too?
Also, do you think I should try using things like wood to lower my ph or should I just get rid of the sand altogether

My ph is between 8 and 9 and my fish are fine but all I have is bettas, cories and otos (and snails). I haven't check ph since adding the wood, I should do that right now........

OK it's still darker than the 7.6 color on the card.

The gravel I got at a LPS and you can tell by looking at it that it's real little smooth-ish rocks, not the rough colored gravel people usually get at the store. I also bought several bags of smooth little glass pebbles (like for flower arrangements) at a craft store and mixed those in. I will add on a photo of my fish where you can see the gravel kind of close up. The green and white ones are the glass: