Rocks in my tank

[mel_20_20]

I want to build a cave, and also, I want to put rocks in water in the sun to grow some algae for my otos and brochis; is a sandstone type of rock OK or does it need to be a less porous type, such as granite?

These were pieces left over from some rock work on my house.

I scrubbed them, soaked them in mild bleach water, then have been soaking them in water with de-chlorinator.... is there anything else I should do?

Thanks

 

[Lupin]

Bronchis really don't eat algae. Your rocks should be ready for use.

 

[Rbishop]

I would use more of a non-porous rock.

 

[Notophthalmus]

Two things to be wary of:

1) If the sandstone is very gritty and feels abrasive to the touch, it will probably be abrasive to your fish's mouths as well.

2) Some sandstones contain calcium carbonate and may affect your water chemistry. You can try the bucket test- fill two buckets with tap water or tank water, placing your rocks in one; test pH, GH, and KH of both when you fill them and then again a few days later. If the water chemistry is substantially the same then they are inert.

I have found fine-grained limestones to be excellent algae substrates, but they are definitely capable of altering your water chemistry. Chert and flint work as well and are inert and non-abrasive, though they may have sharp corners. I haven't tried granite.

 

[mel_20_20]

OK, this sandstone is pretty gritty/sandy feeling. I kinda worried about how this would feel on the mouth. It's beautiful, with color striation throughout, but I don't want to hurt their mouths.

Where do I get flint, and what the heck is chert?
Uh. I guess I can get the flint and ?chert?....
at a stoneyard .....where a builder gets stones for.......
stonework. duh!

Sometimes I amaze myself at my Holmesian deductive powers. :headshake2:

I will check that out, unless we fishy people have another handy, convenient, economical source for rocks for our fishy friend's homes.:goldfish:

Where I live, the only stones and rocks you can just go find, lying around or in the ground, are ugly ironstone.
Suggestions are appreciated.