How To Ensure Your Aquarium’s Water Is Fish Friendly

One of the biggest challenges, when you start out building an aquarium, is to make sure the water in the tank is perfect for the fish you want to keep. Water chemistry is important for most animals but for marine fish, it is even more vital.

Getting the right mix of salt, water and nutrients in your aquarium’s water supply is the biggest challenge, and the solution involves purifying the water, adding the right amount of salt, and installing a live rock to help filtrate the water.

Purifying Water

Water from the tap is safe to drink for humans, but the reason for this is that it goes through a complex treatment process that involves the use of disinfectants such as chlorine, which kills bacteria and other organisms.

Most marine fish cannot handle tap water in its natural state, so the water may need to be purified. A marine test kit can check the nutrient levels of your water and let you know if you need to purify.

This can be done in three ways:

• Reverse Osmosis – This is where water is filtered under pressure through a membrane, producing a small amount of pure water.
• Deionisation – This is where charged particles are bound to a special resin, leaving pure water to flow through.
• Ion Exchange – Similar to deionisation, but also displaces sodium and chloride which helps produce seawater.

Adding Nutrients Back

The next step is to add salt and other minerals back into the water to help replicate the seawater your fish would naturally swim in.

Whilst different species have different needs, a good benchmark is to aim for a salt content similar to natural seawater, which is roughly 35g per litre.