is all white sand non-silicate based?

[Anonymous]

hi.
You can test to see if the sand has carbonate in it by the famous "vinegar test." Basically, add the sand to vinegar, and see if it bubbles. SiO2 is almost complete inert, but carbonate reacts with mild acid.

Vinegar can digest >90% of calcium carbonate with sufficient volume and time. If nothing reacts (bubbles), I am sure that the sand you see is does not contain much carbonate, if any at all.

 

[kyguy]

I have had absolutely no luck trying to get southdown sand here in kentucky. I have found one other brand of white sand, made by oldcastle. their website was totally useless. I have searched the bag, with no sign of the 'warning, contains silicate' label, and the garden shop manager was clueless. Has anyone else either heard of this brand, or had any experience with a white sand which was silicate based? most playsand that I have run into seems to be yellowish, and this stuff was the extra $1.50 over regular playsand that I would expect for an araganite based sand. Anyone have any other info please?
thanks in advance-

 

[MattM]

It probably is a silica based sand. If it's mostly quartz (SiO2), then it will be very white.

FYI - anecdotal reports by many aquarists have reported no major problems using silica sands. At normal tank pH, the quartz does not break down. I would be curious what the pH is deep in the sand bed, and whether that is low enough to result in Si release, but there it is...