DOs & DON’Ts of Setting Up and Cycling A New Jellyfish Aquarium

Here’s some quick tips about how to properly set up a new aquarium specifically for jellyfish and things to look out for when your tank is cycling.


  • DO use new saltwater with the following baseline water quality parameters:
    • Temperature = 65-78°F
    • Salinity = 31-33 ppt or 1.023-24 SG
    • pH = 8.0-8.1
    • These are the optimal water quality parameters for keeping moon jellyfish happy and healthy
  • DON’T add any buffers, conditioners, or additives to your aquarium water before, during, or after the cycle
    • These can throw off the water quality and disrupt or inhibit the cycle from starting
  • DO use Instant Ocean Sea Salt mix for your saltwater as it has no buffers, conditioners, or additives [Purchase from Amazon here]
  • DON’T use any salt mix labeled as “reef salt,” “pH balanced,” “probiotic,” or “enriched”
    • These tends to have extra minerals, vitamins, and higher levels of pH specific for corals, anemones, etc. in reef tanks, that jellyfish do not need
  • DO make sure your pump is plugged in, turned on, and working properly before starting the cycling process
  • DON’T keep your tank near windows and/or in direct sunlight to keep algal growth at a minimum
  • DO add distilled/RO water to compensate for evaporation (evaporation causes salinity to rise; adding freshwater helps to bring it back down)
    • Evaporation is noticeable when the water level is lower than where it started
  • DON’T add distilled/RO water near the filters – this can completely wipe out your growing bacteria colonies
    • Only add freshwater to the main viewing area and away from any direct contact with jellyfish
  • DO keep a record of weekly water quality readings, especially when cycling
  • DON’T use test strips as they often give unreliable readings
  • DO start the cycling process with a newly setup aquarium.
    • If your aquarium has been running with saltwater & the bio starter bacteria for longer than a week, you will need to dump the water and start over with all new saltwater & new bacteria.
  • DON’T perform any water or filter changes during cycling
    • This can disturb the growing beneficial bacteria and disrupt the cycle
  • DO keep an eye on the piece of shrimp in your tank when cycling (when using the “fish-less” cycling method)
    • Sometimes it can completely disintegrate before the cycle is over and will need to be replaced to keep the ammonia production up
  • DON’T freak out if your cycle isn’t exactly on track 
    • Every cycle is different and sometimes an aquarium needs an extra week to catch up
  • DON’T add a bubbler if you own a Cubic Orbit 20 jellyfish aquarium until after your tank has completely cycled
    • Since the pH naturally lowers during the cycling process, aeration can inhibit the cycle from starting

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