A gravel bed does two jobs in a tank most owners never think about: it holds plants and ornaments in place, and it sits under a colony of bacteria that helps keep the water clean. Get the wrong material and the second job can go wrong quietly, long before anyone notices a problem in the water itself.

Marina's Beach Pebble is a completely natural gravel, chosen for the look rather than any coating, and Marina state it will not affect water chemistry or harm fish. It gives plants and ornaments a solid base to be anchored into, which matters more than it sounds once a tank has any current running through it.

• Completely natural gravel, no dye or coating
• Sold as a 2kg bag
• Marina state it will not affect water chemistry
• Provides a solid substrate for anchoring ornaments and plants
• Suitable as an aquarium substrate generally

On what is not stated. Marina do not tell us the pebble size or grade this bag is graded to, so if you are matching an existing substrate or need a specific stone size for a planted setup, you will not get that detail from the packaging facts we have. Being natural stone, expect some variation in colour and shape between pieces.

Who it's for: anyone setting up or topping up an aquarium who wants an inert, natural-looking gravel rather than a bright dyed one, and does not need a specific pebble grade.