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Last updated at 04/06/2026 03:53:45

Please note: price history and price alerts are not available for some stores, including Amazon.com.au.
Amazon.com.au

$55.97

Seachem Onyx Gravel, 7 kg / 15.4 lbs, Aquarium Substrate, Ideal for Marine, Freshwater, Reef, Planted, Cichlid Environments

Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!

Aquaristic Online

$59.00

Seachem Onyx 7kg

Delivery $14

Coburg Aquarium

$60.00

1

Price history

Price history

Please note: price history and price alerts are not available for some stores, including Amazon.com.au.

Reviews

1 August 2019

originally posted on pro-shrimp.co.uk

Excellent, good choice for Malawi tank

19 March 2021bibicax

originally posted on shopee.vn

Ổn

Best Substrate
11 March 2015JHR371

originally posted on 1800petsupplies.com

Seachem products are the best in my book. I've used them for quite sometime in a salt water tank I use to have. Now I started a freshwater tank for my daughter. The tradition carries on.

Specification

Aluminum822
Barium5
Calcium197,500
Cobalt4
Chromium10

Price comparison

Updated 5 days ago
Please note: price history and price alerts are not available for some stores, including Amazon.com.au.
Amazon.com.au

$55.97

Seachem Onyx Gravel, 7 kg / 15.4 lbs, Aquarium Substrate, Ideal for Marine, Freshwater, Reef, Planted, Cichlid Environments

Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!

Aquaristic Online

$59.00

Seachem Onyx 7kg

Delivery $14

Coburg Aquarium

$60.00

1

Price history

Price history

Please note: price history and price alerts are not available for some stores, including Amazon.com.au.

Reviews

1 August 2019

Excellent, good choice for Malawi tank

originally posted on pro-shrimp.co.uk
19 March 2021

Ổn

bibicax originally posted on shopee.vn
Best Substrate
11 March 2015

Seachem products are the best in my book. I've used them for quite sometime in a salt water tank I use to have. Now I started a freshwater tank for my daughter. The tradition carries on.

JHR371 originally posted on 1800petsupplies.com

Specification

Aluminum822
Barium5
Calcium197,500
Cobalt4
Chromium10

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- 3%
Seachem Onyx Gravel - 7 kg/15.4 lbs
Seachem Onyx Gravel - 7 kg/15.4 lbs
Seachem Onyx Gravel - 7 kg/15.4 lbs

Seachem Onyx Gravel - 7 kg/15.4 lbs

(9 reviews)

Seachem Onyx Gravel - 7 kg/15.4 lbs

$55.97

(9 reviews)

Onyx Gravel is a specially fracted, stable porous clay gravel for the natural planted aquarium. Its appearance is best suited to planted aquaria, but may be used in any aquarium environment. Being carbonate rich, Onyx Sanda provides an advantage to any plants able to utilize bicarbonates. Although ideally suited to planted aquaria, it may be used in any aquarium environment. Onyx Sanda is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels. Gravel modifiers such as laterite are not necessary. Onyx Sanda is not chemically coated or treated and will not alter the pH of the water. Although pre-washed, it may be rinsed before use to remove residual dust. Dust can also be minimized by filling aquarium slowly and dispersing water so that the Onyx Sanda bed is not disturbed. Slight initial cloudiness is normal and will clear rapidly (2Ð12 hours). To shorten the cloudiness period use Claritya in conjuction with mechanical filtration (such as filter floss).

Onyx Gravel is a specially fracted, stable porous clay gravel for the natural planted aquarium. Its appearance is best suited to planted aquaria, but may be used in any aquarium environment. Being carbonate rich, Onyx Sanda provides an advantage to any plants able to utilize bicarbonates. Although ideally suited to planted aquaria, it may be used in any aquarium environment. Onyx Sanda is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels. Gravel modifiers such as laterite are not necessary. Onyx Sanda is not chemically coated or treated and will not alter the pH of the water. Although pre-washed, it may be rinsed before use to remove residual dust. Dust can also be minimized by filling aquarium slowly and dispersing water so that the Onyx Sanda bed is not disturbed. Slight initial cloudiness is normal and will clear rapidly (2Ð12 hours). To shorten the cloudiness period use Claritya in conjuction with mechanical filtration (such as filter floss).

Onyx Gravel is a specially fracted, stable porous clay gravel for the natural planted aquarium. Its appearance is best suited to planted aquaria, but may be used in any aquarium environment. Being carbonate rich, Onyx Sanda provides an advantage to any plants able to utilize bicarbonates. Although ideally suited to planted aquaria, it may be used in any aquarium environment. Onyx Sanda is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels. Gravel modifiers such as laterite are not necessary. Onyx Sanda is not chemically coated or treated and will not alter the pH of the water. Although pre-washed, it may be rinsed before use to remove residual dust. Dust can also be minimized by filling aquarium slowly and dispersing water so that the Onyx Sanda bed is not disturbed. Slight initial cloudiness is normal and will clear rapidly (2Ð12 hours). To shorten the cloudiness period use Claritya in conjuction with mechanical filtration (such as filter floss).

Onyx Gravel is a specially fracted, stable porous clay gravel for the natural planted aquarium. Its appearance is best suited to planted aquaria, but may be used in any aquarium environment. Being carbonate rich, Onyx Sanda provides an advantage to any plants able to utilize bicarbonates. Although ideally suited to planted aquaria, it may be used in any aquarium environment. Onyx Sanda is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels. Gravel modifiers such as laterite are not necessary. Onyx Sanda is not chemically coated or treated and will not alter the pH of the water. Although pre-washed, it may be rinsed before use to remove residual dust. Dust can also be minimized by filling aquarium slowly and dispersing water so that the Onyx Sanda bed is not disturbed. Slight initial cloudiness is normal and will clear rapidly (2Ð12 hours). To shorten the cloudiness period use Claritya in conjuction with mechanical filtration (such as filter floss).

$55.97 - $60.00

in 3 offers

The lowest price for Seachem Onyx Gravel - 7 kg/15.4 lbs right now is $55.97 at Amazon.com.au, compared across 3 retailers.

The all-time low was $51.02 on 25 Apr 2026 — today's price is 10% above the lowest ever. That's a little above the best price we've seen.

Prices last updated 4 June 2026.