"Katra" wrote in message
...
In article ,
"Bill Stock" wrote:

"Starfish" wrote in message
...
Hi everyone! ;-)

I was just wondering if a fine layer (1cm or less) of coarse dark sand
would be ok for a fish tank.....i just want to provide some contrast
with
the fish and to give the tank a natural look without going to heavy
with
the substrate.

Does anyone have any reccomendations into types of dark brown coarse
sand
to use?

TIA

Starfish


I went for the red river rock, but I saw it in black as well. I just
bought
enough to cover the bottom of the tank. I needed about 30 lbs to cover
the
bottom of my 75 gallon. It hides the mulm, but is much cleaner than
gravel.

The only down side is the algae! My reddish rocks are now mostly bright
green, but it keeps the GF busy moving them around.



Is native Limestone ok to use for tanks? Or will it dissolve too much
and make the water too alkaline? There is literally tons of that pretty
stuff laying all over the ground in our area! Both with and without
holes.


It would depend somewhat on the PH of your tap water. A lot of people add
the limestone/coral to their filters to prevent PH swings. I had a PH crash
in my previous tank (gravel with too much mulm), so I added crushed coral to
my filter to stabilize my PH at around 7.8. Fortunately my tap water has a
PH around 7.5, except for the cooler months. So water changes don't give the
fish too much PH shock. But if your tap water had a PH of 6 and your tank
was at 7.8, then water changes would be an issue. You would have to adjust
the tap water's PH before adding it to the tank.

The best thing to do would be to put some limestone in a test bucket of
water for a couple of weeks and the test the water's parameters. Make sure
you wash the rock well before doing your test. Once batch of crushed
limestone that I tested had severe Nitrate content, but it was fine after I
washed it.