Water quality is the most important part of keeping jellyfish

It’s therefore important to keep your tank healthy and clean for your jellies.

Water Quality Tips

These are the most commonly asked questions regarding water quality.

It’s recommended to use a saltwater test kit to test the quality of your salt water before jellyfish are added.

  • Proper Water Cycle: Before adding jellyfish to a new tank, the water should be “cycled”, to ensure helpful bacteria are in place, and allow your jellyfish to have a proper healthy home. Read our Help and Advice article on How to Cycle your Jellyfish Tank for help.
  • Remove Uneaten Food: Our tanks are supplied with a pipette to easily remove uneaten food and other debris. To keep your water clean, you should remove uneaten food either daily or every other day. Note that this is only an issue if feeding with dried food, consider feeding live food to reduce on uneaten food debris.
  • 10-14 Day 10-25% Water Change: Keeping the water clean is achieved by replacing 10-25% of the aquarium’s water every 10-14 days. So be sure to have a supply of Salted RO Water ready for these changes. If you have a Jellyfish Art Cylinder Nano tank, then a 2 litre weekly water change is usually sufficient (remember to test your water before and after).


For the species we provide, room temperature is fine and no heater or chiller is required unless in exceptional circumstances. Our jellyfish tanks are therefore sold ready to go!

If keeping more exotic species, then the temperature must be adjusted to suit the species of jellyfish that you are keeping in the tank.

All of our tanks come with external connections built in, for the addition of heaters or chillers, if you deem this to be necessary.

For Aurelia species – commonly known as the Moon Jellyfish – a temperature between 16-20°C is advised.


We provide a Hydrometer with all of our jellyfish tanks to easily test water salinity – your salt water should have an SG rating of between 1.024 – 1.026.

Although some jellyfish can tolerate a wide salinity range, it is generally still recommended to house them in water with a salinity close to that of natural seawater, usually 34-35ppt.

Other Water Parameters

It’s rare that any amendments are required to other water parameters – generally you should stay away from additives or any chemicals which could simply upset jellyfish in the long run.

Figures to aim for are as follows:

pH: 8.1 – 8.4
NH3 = 0.0 ppm NO2 < 0.05 ppm NO3 < 10.0 ppm
PO4 < 2.0 ppm Alkalinity 7.4 – 8.4 DkH

These should be monitored and maintained by way of regular partial water changes (the 10-14 day 10-25% water change). Stick to your regular weekly water changes and continued maintenance of your tank, removing uneaten food daily for example, and these water parameters should be easily maintained.

Remember that we stock replacement filters and accessories to keep your tank clean: