Saltwater Mixing | Water Preparation | Filling and Powering the Aquarium

Living Oceans

How to Mix Saltwater and Refill Your Aquarium After a Water Change

After completing a water change, the next step is to prepare fresh saltwater and safely refill your Living Oceans aquarium.

Taking a little extra time to mix the water correctly helps maintain a stable, healthy environment for your fish and corals.

Before You Begin

Prepare your workspace before mixing the new water.

We recommend:

  • laying towels on the floor and cabinet to catch any spills
  • switching off power to the aquarium
  • washing your hands or wearing aquarium-safe gloves if needed
  • removing the mesh lid and safely resting the light on its cable
  • gathering your buckets, pump, hose, water conditioner, and hydrometer

Saltwater can corrode metal surfaces, so it's worth cleaning up any spills as you go.

Mixing the Saltwater

Use filtered tap water with minimal chlorine, nutrients, and heavy metals whenever possible.

To prepare approximately 45 litres of saltwater:

  1. Fill a 20-litre bucket with 15 litres of fresh water and pour it into the larger mixing bucket.
  2. Continue filling until you have 45 litres of water.
  3. Add the recommended dose of water conditioner according to the product label.
  4. Add marine salt at a ratio of 300 mL of salt for every 10 litres of water.
  5. Stir until the salt has completely dissolved.

Check the Salinity

Before adding the water to your aquarium, check the salinity using the floating hydrometer.

Allow it to settle and aim for a reading of approximately 1.024, or within the green indicator range.

If required:

  • add more salt to increase salinity
  • add fresh water to reduce salinity

Taking a few moments to check the salinity helps avoid unnecessary stress on your livestock.

Match the Temperature

Slowly warm the new saltwater to 24°C before refilling the aquarium.

A simple way to do this is by adding small amounts of hot water, checking the temperature as you go until it matches the aquarium.

Refilling the Aquarium

Before starting the pump, make sure the valve on the hose is closed.

Then:

  1. Plug in the pump.
  2. Open the valve to begin filling the aquarium.
  3. Stay with the aquarium while the pump is running.
  4. Close the valve and unplug the pump once the bucket is empty.

Repeat the mixing and filling process until the aquarium reaches the overflow chamber and water begins flowing into the filter baskets.

Never leave a running pump or siphon unattended.

Restart the Aquarium

Before restoring power:

  • unplug the Auto Top Off (ATO) system
  • turn the aquarium back on
  • top up the pump chamber with around 3 litres of prepared saltwater until the green ATO sensor is submerged
  • adjust the circulation pump nozzle so it sits horizontally, pointing towards the centre of the aquarium

Avoid aiming the nozzle upwards, as excessive surface agitation can create noise and salt creep.

Once the water level is stable, reconnect the ATO. The sensor will flash green before changing to a solid green light, indicating normal operation.

Final Checks

To finish:

  • replace the mesh lid
  • secure the light cable beneath the auto feeder without restricting its movement
  • reinstall the aquarium light
  • wipe away any water splashes from the glass and cabinet

It's normal for the water to appear cloudy for a few hours after maintenance. Corals may also remain partially closed before opening again over the next few hours or even a couple of days.

With the correct water parameters restored, your Living Oceans aquarium will quickly settle back into its natural balance.