Depending on the water quality of your jellyfish tank, a 10-25% change of water every 7-14 days should be carried out.

Remember you must always be using Salted RO (Reverse Osmosis) Water, at SG 1.025 – tap water will not do!

Changing some of your tank’s water weekly will improve the quality of your water, and allow your jellyfish to live longer.

Consider: Taking proper care of your jellyfish tank will create less work for you in the long run, and will avoid chasing runaway water parameters where things have gotten bad!

Tip: Test your water before and after a water change, to know where you started and how it finished!

How Do We Change Water?

There are many ways to perform a water change, from a simple “in and out” – taking water out and replacing it with the same amount – to actually removing the jellyfish from the tank to aid with cleaning at the same time.

First things first, use a test kit, to identify what your water parameters are like prior to the water change – and test again after. Water tests should be part of your care regime, allowing you to always keep on top of what your water is doing.

“In and Out” Method

This method is recommended for most water changes.

Easy enough, use a pipette or a syphon to remove a sufficient quantity of water. With a Jellyfish Art Cylinder Nano, this is normally about 2 litres.

Replace with fresh Salted RO Water (at SG 1.025), making sure to add this to the back of the tank (where the black sponge filter is).

Try to add the new water slowly, to avoid a build up of water bubbles and excessive water flow.

Remember to add JellyBio Maintain to the new water before it’s added to the tank. 1 cap-ful of JellyBio Maintain is sufficient if you are changing 2 litres at a time.

Tip: Make sure the water you’re adding is not a totally different temperature as the water in the tank – i.e. consider where your water has been stored, if it’s kept outside in the cold, for example in a garage, then bring it indoors to warm up again first.

Removing Jellyfish Method

This method allows for a much deeper clean, ideal for a monthly scrub, or whenever seems appropriate. Remember all tanks are different, depending on the tank’s location, food source, and so on – therefore there is no set timescale for when a “deep clean” might be suitable.

Removing the Jellies

If removing jellyfish, provide a suitable location for them to go in the meantime. An “aquarium use only” bowl for example, would suffice.

Fill your container with enough water (from their tank), so that when the jellyfish are added, then can swim, without being exposed to the air.

Use a ladle, or similar, to gently remove each jellyfish one at a time, and place in your container. The jellies can comfortably sit here while you complete your water change.

Performing a deep clean

Use an acrylic friendly brush (Jellyfish Art tanks come with one of these) to scrub away any uneaten food and algae which may have appeared within the tank.

Use a pipette (Jellyfish Art tanks come with one of these) to remove bigger chunks of debris which should now be floating around the tank.

Use a syphon to remove water (usually around 2 litres for a Jellyfish Art Nano tank), and replace with new Salted RO Water.

Remember to add JellyBio Maintain to the new water before it’s added to the tank. 1 cap-ful of JellyBio Maintain is sufficient if you are changing 2 litres at a time.

Replacing the Jellies

First, check your tank, and brush away any bubbles that may now be present as a result of the water change. Stray bubbles can push holes through a delicate jellyfish, so it’s important these aren’t present.

Once your deep clean has been completed, the jellies can be returned to the tank. Again, be gentle with them, and ensure they aren’t exposed to air.

Consider: How long have they been out of the tank? How different is the water temperature in their bowl compared to the water temperature in the tank?

What Water Should We Use?

Under no circumstances should tap water be used. Jellyfish Tanks need “Salted RO Water”, which is easily available pre-mixed from most aquatic shops, or you can mix your own.

Pre-Mixed Water

We supply Caribsea Sea Pure Saltwater, a Salted RO Water which is already mixed to SG 1.025 (the required salinity for a jellyfish aquarium) – this is sold in 16.66L bottles, making it ideal for water changes.

You can also visit most aquatic shops (we have an Aquatics Shop Finder Here) who will supply Salted RO Water pre-mixed to SG 1.025, usually for a very inexpensive price.

The frequency of water changes depends largely on the method of jellyfish feeding, as some methods may degrade water quality more than others. For example dried food, will dirty the water much quicker than live food.

If mixing your own water…

It is important to test the water regularly so that it remains in acceptable ranges of salinity. If mixing your own water, then the water must be prepared at least a day before the water change proper and left overnight with aeration, as some elements in salt water require a long time to dissolve (roughly 24 hours).

Newly mixed saltwater is very unstable, even when it seems that most of the salt has disappeared. This may cause stress on your jellyfish and in extreme cases, death.  When doing the water change, stop the pump and other machines like the heater and chiller. Use a hose and bucket and begin siphoning water from your aquarium into the bucket.

How Much Water Should We Change?

For a Jellyfish Art Cylinder Nano tank, we recommend to change 2 litres (25%) every week (7-10 days).

This is a recommendation for most tanks, but the amount to change will depend on a few factors – number of jellies, type of food being used, regularity of feeding. No tank is the same. Use a test kit to identify what your water parameters are looking like, to therefore identify when a water change is appropriate.

Typically between 10 and 25% is sufficient for most tanks on a weekly basis.

Monthly Water Changes

Remember that every 4 weeks, certain items in your tank may also need replacing or rinsing.

  • Replace Chemi-Pure Blue Nano packet every 4 weeks.
  • Rinse the black filter sponge (with Salted RO Water) every 4 weeks.

Tip: You can use saltwater from a water change to rinse the sponge filter, the rinsing is only to rid the sponge of any trapped debris such as uneaten food.

Tip: Make sure to rinse the Chemi-Pure Blue Nano packet with saltwater prior to adding it to the tank.

Tips for Completing a Water Change

Use a siphon to easily transfer water from one location to another.

The speed of the siphon can be controlled by raising or lowering the bucket compared to the height of the water in your aquarium or by pinching the syphon tube. Controlling the speed of the siphon is important in order to not risk sucking up you jellyfish and potentially damaging it.

Once the 10-20% of tank water has been successfully siphoned out, replace it with your prepared seawater through the filter compartment slowly. This will limit the chances of creating air bubbles that may harm the jellyfish.

If any air bubbles get caught on a jellyfish, gently turn it over and slowly massage the bubbles free.