Silica sand?

[plaalye]

Hi all, I'm in search of a substrate or my rivertank. I'd like to go sand or very small, rounded gravel.I just came from Home Depot and they have a 100lb bag of "silica sand" for $6.99. It's nice and white with obvious shiny specs of silica in it. It seems I've read somewhere that silica can cause problems in a tank? I know Emma told me that the substrate in her lovely rivertank is black silica sand. Can anyone clarify this for me. Are there different forms of silica? Thanks much!

[Laura]

I understand your concern as I also found on-line reports of problems with silica sand/pool filter sand (PFS). Some comments suggested that it was sharp and would damage fish gills. Contrary to that, I knew that lots of very experienced fish keepers here used PFS. I decided to assume that if it worked for them, then it must be okay.

I needed to switch out my substrate from gravel to a finer material and wanted something that my dojos could dig into, and was suitable for my goldfish. I decided to take the plunge and got the largest grain PFS I could find, I think they called it #10.

I haven't any concerns with it. My goldfish take in and spit out mouthfulls, and my dojos hide in it, and filter it through their gills. It's been a couple of months and I would use it in another tank without hesitation. I can't comment on your question as to whether there are different types.

Make sure you wash it well before putting it in the tank. if you do a search on 'silica' there are lots of hits which have tips on using sand.

[Diana]

Try a rock yard or masonry yard. Look for a product called Lapis Lustre. This is a sand that is sold in bags, it is graded into many different sizes. One store near me sells about 5 different grades of the stuff!
It is generally more rounded, not sharp. The finer grade (30 mesh) is good I actually use pool filter sand that is 30 mesh, and have clowns and yoyos in this tank. No anaerobic spots, and the fish all have intact barbels and are not getting hurt by this sand. There are coarser sands available in the Lapis Lustre product line, the coarsest is almost like a very fine gravel. It is called 'Aquarium Sand'.

Silica will grow brown algae (Diatoms) for a month or two, until the free silica is used up. Many fish will eat the diatoms, and each time you remove the poop and scrape off and remove the diatoms you are removing the silica from the tank. I had a beautiful bloom of brown algae in a couple of tanks and found Mollies were great at removing it, but this was in a couple of low end brackish tanks.

Part of the problem with sand is that a sand that is not sorted or graded will have particles of many sizes and it will pack down in a tank with the potential of causing anaerobic pockets where certain bacteria grow that produce toxic substances.

[jones57742]

plaalye:

This post is adding to and based on Laura's and Diana's post.

Sand is the typical definition of a very small granular material which is substantially chemically inert.

Many sands exist including but obviously not limited to siliceous, basaltic, granitic, etc.

Particulate materials which are not inert are typically refereed to as fines, ie crushed coral, etc.

IMHO, a sand will work in your aquarium but I need to qualify.


Out in the "sand world" two principal types exist.

Well graded sand is No Good as the grain sizes vary and will compact to virtually optimum density subject to hydrostatic pressure.

Uniformly graded sand contains grains which are of a typical size.

TR

[plaalye]

Thanks all for your responses! That's about what I've gathered also in my reading but I wanted to get the OK from you all, who I consider the best. The Diatoms and anaerobic pockets were my concerns. The silica sand at Home depot is finer than I want. The 30 mesh sounds about right. I spent several hours today looking for Masonry or pool supply shops to no avail. Will keep trying. Thanks again!!

[jones57742]

... Will keep trying. ...

pl: I somehow missed this earlier.

Go to one or more concrete plants in Bellingham.

They should be more than happy to give you (or sell you at minimal cost) the type of sand your are looking for and you may like the gravel that they have also.

If you find some sand and/or gravel which you like at a concrete plant but the batcher starts giving you problems ask for the owner's and manager's name and phone numbers.

I will call them and splain to them by hand.

TR

[plaalye]

Thanks TR
I found a likely prospect at the end of the day but they were closed.I'll try again Monday.