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Marine Salt & Substrates

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15 Item(s)
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Reef and marine salt suitable for both ready mixed salt and pre-filtered water environments. Also see our sand, live sand, gravel and specialist planting substrates.

Swallow Aquatics offers a complete range of marine salt, sand, gravel and specialist planting substrates available for order online. Our range of reef and marine salt includes products suitable for pre-filtered and ready mixed salt water.

Fish Tank Substrates - FAQ

Choosing a quality substrate can dramatically improve plant growth in your aquarium, while making your tank look even more attractive.

How Much Sand/Gravel Do I Need?

Although substrate is sold by weight, it is actually the volume or depth of the substrate that you need to consider.

For sand substrates, the rule of thumb is you’ll need a depth of 2.5cm/1 inch at the bottom of your fish tank.

Gravel on the other hand, requires a deeper layer of substrate – perhaps 5cm to 2 inches or so.

To determine how much substrate to buy, first consider that dry sand weighs about 1.95kg per litre, while gravel weighs about 1kg per litre. Next, determine the volume of substrate you require for your aquarium, and multiply this figure by the weight of a litre of the substrate you prefer - either sand or gravel.

What Diameter of Substrate Should I Go For?

It is important to remember that some fish, such as goldfish, rays, eels and many catfish are bottom feeders who like to sift the substrate for food. If you intend on keeping bottom feeders, fine sand is definitely the ideal choice.

While large-grained gravel can be used when keeping most mid and top feeding fish, it is important to remember that the larger the grain-size, the larger the gaps between the grains. Therefore substrate with a greater diameter makes it easier for dirt to become lodged in between the grains. This makes cleaning more labour intensive and you’ll likely require a gravel cleaner.

Should I Buy a Coloured Gravel Substrate?

If you intend to keep fish that require neutral or soft water, it’s not a good idea to put coloured gravel in your tank. The majority of coloured gravels consist of white dolomite, which is a naturally occurring mineral that is high in magnesium and calcium. This substance can boost the pH, hardness and alkalinity of the water in your fish tank, which can upset some species of fish.

On the other hand, if you live in an area that supplies hard water anyway, or are intending on keeping goldfish which don’t mind higher alkalinity, coloured substrate is fine to use – and may make your tank look even more exciting!


Marine Salt

How Much Marine or Reef Salt Do I Need?

Well that depends on the size of your tank, how many tanks you have, and the level of dedication you have to your aquatics hobby!

Junior hobbyists and nano-aquarium owners should ideally only purchase small 2kg packages of marine salt, to avoid overspending and potentially being stuck with a large bucket of salt that they won’t end up using.

On the other hand, dedicated aquatics enthusiasts with one or more large fish tanks will probably find that purchasing a 20 or 25kg bucket is the most cost effective solution.

For more advice on marine salt and substrate, why not speak to someone from the friendly Swallow Aquatics team?