Various Sands and Mineral Substrates Compared

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Fish Herder
Jan 26, 2021
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Nanaimo, BC
I am always on the lookout for unique hardscape and substrate material, either purchased or preferably self collected. Right now I am using a version of QuikCrete Play sand in most of my tanks but I have gone through a whole gamut of other types of substrate. What I am really looking for is a sand like is found on the North Shore of Lake Superior, where my father and I collected gravel for his tanks around 1973, deep orangey red tones with some black and white grains. He kept that gravel until the 2000s when it finally was lost.

I tend to like sands that are more uniform in size, and the play sand I use in my aquarium has been sieved to get a particle size of 0.2 mm to 2 mm, which would be considered medium to very coarse sand according to the Wentworth Size Classification I feel this size range prevents gas generation (hydrogen sulfide) because it isn't so packed together that gases from decomposition can be released, and it allows some very restricted water flow, though a lot of this is based on simple personal opinion.

To cut to the chase here are some of the sands I have used. All photos are enlarged the same amount so you can use direct comparison.

Pool Filter Sand, Silica based though I don't know if it is crystalline or amorphous, size is mostly 0.25 to 1.0 mm. I would still be using it except it is totally too bright. By design this material does not compact. Particles are very rounded and maintain the ability to allow water to flow through. Only minor rinsing before use.

Black Florite Sand - This is a manufactured product, quite expensive. Particles range from 0.05 mm to 3.0 mm. This material has been heavily rinsed before use removing about 2 cups of powder like fines from an 8kg bag (my 60 gallon used 5 bags of this material). The sand looks good to me when in the tank but it does seem to compact. In addition you can see how angular the particles are. Not knowing better I had some corys in with this material and they did not like it at all. I thought my plants might do good in this material but they didn't do any better than anything else, additionally the root tabs in this substrate seem to hardly have been broken down. The one major issue I have with this sand is that it has a lot of particles that are magnetic and will stick to your impeller drive magnets and it is hard to get out. This isn't the only product with the magnetic issue.

The next substrate is QuikCrete play sand. This is directly out of the bag it has a particle size from 0.025mm to 2.0 mm. I don't like the size range because I fear the fine particles will "clog" the space between the larger particles. This material is very dirty and needs to be thoroughly rinsed before use. This material is "cleaned" before being packed by heating, but otherwise this is essentially the raw material based on my personal collection of similar materials from nearby sites. It is inexpensive but if you sieve it to a narrow particle range you will be throwing away a lot of material. The material is partially rounded but still contains some sharper particles. Like the florite above many of the black particles are magnetite and are attracted to the impellor drives, but these particles are larger so it is not as much of an issue as it is with the florite. Given the similarity of this product to my personal collections I would say this comes from the Orca quarry,

Nanaimo River Sand, I recently sieved and collected 1/2 a bucket of this material because it looked darker than any other local sand, unfortunately it wasn't, it looks identical to the sieved play sand. It too has some magnetite particles. It does have some particles to 3mm but the majority are about 1 mm, this is a result of sieving. There is a bit more color in the coarse material but the fines are still the boring peppered beige tone.

The final trial was EnviroGrit 12/50. This is ground glass, I was hoping for more brown beer bottle glass but it is generally a green color. Unfortunately the particles are very sharp looking, but I washed the grit like normal sand or gravel and didn't cut my skin once, I didn't use gloves. The color is kind of a transparent green that I don't care much for. I had an Echinodorus planted in this material without any fertilizer in a fishless tank and when I transported it I was surprised at the growth. I think you could use this for a no bottom fish setup, but I would probably try the 20/50. I thought about putting it in a large tumbler to round the edges off but I didn't like the color, so the experiment stopped there. The other issue is this material is very light so it is hard to keep in place in the tank. It is cheap though, I could do my 75 gallon tank for 30 dollars of this material, it is less expensive than play sand.

I did have aquarium soil for a year in two of my tanks. Unfortunately, once you remove it from the tank you really cannot use it again. It was mixed into our compost units. It worked well for the plants at first but then I started to have an issue with organic buildups, finalizing with a big cyanobacteria bloom.

I would be interested to know other people's experiences with various sands or gravels and how or where they obtained them.
My substrate includes pea pebbles on an outside patio pond, Pool Filter sand, and black diamond blasting sand. You can see the pool filter sand wasn’t washed enough, and formed a silty layer.
The reddish Lake Superior sand was all the rage in the 70s - aquarium fashions. It makes photographing fish hard though.

I'm moving at the end of this week, and am curious about what pool filter sand will be where I'm going. Where I am, I can get a grey version and a brown one. We'll see what's on tap when I go looking. There is a sand quarry at the end of my new street I'll also explore. I like darker colours, but substrate has more to do with what I want to see from fish rather than plant growth questions. Darker coloured sand or gravel brings out darker fish colours, and as long as the substrate is cheap and doesn't release minerals, I'll try it.
I am trying to source two types of materials. One is the Black Diamond coal slag, an industrial supplier in Victoria is supposed to be getting it in mid February, the actual product is Black Beauty, but the SDS sheet is the same between the two companies. The other is garnet grit. I cannot get it unless I buy a pallet and haven't found anyone that will sell me some on the side. I knew of some locations in the interior of BC where I could sieve some garnet and black sand out of the river gravel, but I don't know how I would separate it from the magnetite and hematite.

Perhaps on my next rock collecting trip to the States I will have to collect sand as well. It's always fun to return to Canada, "Do you have anything to declare?", "Yes 200 lbs of rock, and a 100 lbs of sand"

The reddish Lake Superior sand was all the rage in the 70s - aquarium fashions. It makes photographing fish hard though.
Never considered the implication of photographing the fish. Back then we didn't waste much film taking pictures of the fish. Neutral gray or black substrate would be better for photography.
That’s what I have - the black diamond coal slag

That is what I thought your last two pictures showed. I like the look and I will try to get some. Though it is hard to get here on the Island because there isn't that much industry here that uses that type of material. This is where I am jealous of people living in my home state, I am originally from Orange/Fullerton, Orange county, though most of the time I prefer to live on Vancouver Island.

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