If you are lucky and don't have fish or plants in the tank yet or
waiting to be put into the tank you can do what I did when I had onyx
sand. I just dumped each bag into the tank. Then I repeatedly filled
the tank with water, swished the sand around with my hand and drained
it with the python. I repeated a few times and it was still cloudy, so
I left it overnight and the next morning it was fairly clear so I
added plants and started the filter up. By the evening it was crystal
clear.

I agree, however, give it a few rinses only. It seems like you can
rinse onyx sand or flourite forever and not get clear water. You want
all those small particles that make the water look murky though, it's
just a matter of letting them settle to the bottom. It doesn't hurt
the fish or plants any if the tank is cloudy from the addition of the
substrate, it just bothers the eyes when you are peering into what
seems like a pitch black tank.

I did that with a second tank, didn't even bother rinsing onyx sand
and the fish were perfectly happy even though the water was foggy and
you could barely make out the fish.

) wrote in message . com...
Onyx raises the KH a bit with softer waters which is good generally.
Better than adding baking soda. But this wears off after a few months.

I add ground peat to all substrates. Maybe a good handful per sq ft. I
add it the very bottom layer along with dirty mulm from a mature tank
to seed the bacteria and also add a bit to the filter to start that.

Both substrates are the same in most respects plant wise.
Both do well with fine and course root plants.

I think some plants look better in each type of color.

Onyx is a little easier to clean than Flourite.
To rinse: add 1/2 a bag at a time into a 5 gal bucket swirl around and
dump off water. Do that 3x for each 1/2 bag. Rinsing more will not
matter.\
Add peat/mulm then add 1 inch or so of the gravel, mix well. Then top
this layer with 2-3 inches of the gravel.

Regards,
Tom Barr