Questions and answers

Frequently asked questions

Quickly and easily find the right answers to your questions relating to JUWEL products. Our "question and answer database" contains useful tips and answers to frequently asked questions. Start by selecting a topic at the bottom and quickly find the information that you need.


  • Should I place anything between the Aquarium and cabinet?

    NO. The JUWEL aquarium includes a safety base frame which ensures an even distribution of the weight. The use of any support material between the aquarium and cabinet will invalidate your guarantee.

  • How do I start up my aquarium correctly?

    Set up the aquarium in accordance with the instructions for use and assemble the filter. Please ensure the correct positioning of the filter media as shown on the packaging of the filter display box. Remove all plastic packaging from the filter media (carbon sponge, poly pad, Nitrax sponge and optional Cirax/Phorax basket). If you wish to fit backgrounds or filter covers into your aquarium now is the best time to do this. Then place your chosen substrate into the base of the aquarium along with any plants and other decorative items that you have selected, e.g. stones and roots. Then, fill the aquarium with water. Hint: Fill the aquarium through the filter box in order to minimise the disturbance of your décor. Once the aquarium is up and running and the temperature has stabilized consult your specialist retailer on how to mature your filter ready for live stock. The Filter needs bacteria to colonize within the sponges to make it safe for the introduction of Livestock. "

  • What guarantee comes with my JUWEL Aquarium?

    We guarantee all of our products for 2 years from the date of purchase. Filter sponges and fluorescent tubes as well as all components that are subject to normal wear, e.g. the impeller of the pump, are excluded from the guarantee. Any guarantee claim must be substantiated with a valid proof of purchase.


  • Is the lighting dimmable?

    Unfortunatly our T5 light units are not dimmable.

  • Why should I use reflectors?

    There are two reasons to use our reflectors: The first is the fact that they increase the light by 100% which is particularly positive, in the case of planted aquariums. The second reason is one of comfort, by shielding the light you can work in your aquarium with the lights on, being able to see what you are doing is always an advantage.

  • Why cant the fluorescent tubes be switched individually?

    Our tests confirmed that plants prefer stable light conditions, they have difficulty in adapting to varying light conditions and therefore the lighting cannot be switched in individually.

  • Can I use the T5 HiLite tubes for my existing light?

    No, you can only use T5 HiLite tubes in a T5 HiLite light unit as these are fitted with special electronic ballasts and have the correct special sockets for the tubes. T5 and T8 are not interchangeable.

  • What is the spectrum of the tubes?

    The spectrum of the tubes is printed on all packaging and can also be found here in the Gallery.

  • How often should the end caps be replaced?

    The end caps that hold the tubes in place should be changed whenever you replace the tubes or annually which ever comes first. These end caps contain vital seals that prevent water ingress into the light unit itself.

  • Can I convert my aquarium to T5 HiLite?

    Any JUWEL Aquarium that utilises a Multilux light unit (central black bar), i.e. all aquariums of the series Lido, Rio, Vision, Trigon, Panorama and Delta, may be converted by simply replacing the old light unit with a new T5 HiLite version.

  • What is so special about the T5 HiLite lighting?

    When we first looked at T5 lighting the biggest issue was that they were not commercially available in standard sizes for our industry. This would leave parts of the aquarium unlit which was not acceptable to us. This left us no choice but to develop this technology into the common aquarium dimensions in order to ensure the complete illumination over the entire length of the aquariums. As a result, we are able to completely illuminate the entire area of our aquariums with lengths of 60, 80, 100, 120 and 150 cm with high levels of illumination. T5 technology only operates with modern electronic ballasts ensuring the highest electrical efficiency.


  • What is the design of the filter?

    The special Construction of JUWEL internal filter allows the circulating pump to pull water from both the upper and lower areas of the aquarium. The water passes through the graduated filter media from the top to the bottom, which greatly simplifies the filter maintenance. The filter media are: The white poly pad which act as a mechanical pre-filter. Hint: Quick and simple to replace, it removes large particle waste preventing the rest of the filter from clogging too quickly. The black carbon sponge removes chemical impurities. The green Nitrax sponge contains special microorganisms that break down nitrate and consequently helps reduce the growth of algae. The blue, coarse filter sponge is biological filter stage I. Separation of the water flow Part 1 of the filtered water returns directly via the riser of the pump into the aquarium. Part 2 of the filtered water moves to the second stage of the biological filtration ""slow filter"". Cirax, the white basket houses filter ceramics with large surface areas under aerobic (oxygen-enriched) conditions. The blue, fine filter sponge represents biological filter stage II which operates in a strong manner under anaerobic (oxygen-deficient) conditions. The filtered water then flows back into the aquarium via the circulation pump.

  • How does the JUWEL filter system works?

    The JUWEL internal Bioflow filter system is a biologically operating aquarium filter. The filter is matched to the aquarium volume for optimum performance The capacity of the filter pump is designed for two or more times the throughput per hour (e.g. Rio 180 = 180 litres with a pump capacity of 600 l/hr) This large and structured filter volume in all our systems provides a safe and stable environment for the livestock along with ease of maintenance. The various structured media within the JUWEL internal filter system is optimised to biologically break down pollutants within the aquarium. The dual flow principle: A unique feature of the JUWEL internal filter is the dual flow principle in the Bioflow 3.0, 6.0 and 8.0. The water passes through the two high volume filter blocks at different speeds for Increased optimisation of the biological filter process. Scientifically tested: Scientific long-term tests by independent institutes have proven that the JUWEL internal filter provides best water quality ensuring a safe and healthy environment within your aquarium. At Juwel we believe the water should stay in the aquarium, that's why our filters are there. This provides peace of mind and along with its exceptional ease of use and maintenance provides a perfect filter system.

  • What is the best method for me to maintain the filter?

    Below are our guideline maintenance suggestions, It goes without saying that the manner and the frequency of the maintenance will also depend on the individual conditions. Our recommendations to clean or replace the media are based on average experiences: Replace the white poly pad on a weekly basis. Replace the black carbon sponge approx. every month. Replace the green Nitrax sponge every 2 months. Replace the blue, coarse filter sponge after approx. 3 months. Replace the white Cirax filter basket with ceramics after approx. 12 months. Replace the blue, fine filter sponge after approx. 9-12 months. (Also refer to the attached figure.) Hints: For safety reasons, always disconnect all electrical devices from the mains before undertaking any work in the aquarium. Never replace all blue filter media at the same time. Check the water level in the filter at regular intervals; a drop in water level indicates that the filter media is beginning to clog and should be changed.

  • Where do I insert Cirax into my existing filter?

    We recommend inserting Cirax at the top spot in the lower filter insert.

  • What is an impeller?

    The impeller is the small rotor equipped with a magnet in the circulation pump. It should be replaced every 12 months in order to ensure the operating quietness.

  • The water flow from my pump seems to be reduced?

    As the filter starts to do its job the filter media clogs and as such the water quantity passing through the filter is reduced. This can be seen by a reduction in the water level inside the filter box. The capacity of the pumps is designed to have sufficient reserves to cope with this. Hint: Check the water level in the filter housing during the weekly replacement of the white poly pad. The weekly maintenance of this white poly pad should restore the level.

  • Which filter system do I have?

    The respective information on which filter you have can be found in the aquarium passport which is in the Instruction manual.

  • How do I identify a Bioflow filter?

    The Biolow pump housing has a diamond shaped connector and sits beside the filter media in the filter housing. Advantage: With the Bioflow Filter you can access all the filter media without having to remove the pump.

  • Can I fit bigger pumps into my filter?

    All JUWEL filters that have 400,600 & 1000 circulation pumps can be interchanged to increase or decrease the flow rates as required. The only exceptions are the 280 and 1500 circulation pumps that cannot be interchanged.


  • Which material is used for JUWEL backgrounds and filter covers?

    All JUWEL backgrounds and filter covers are made of highly condensed polyurethane and coated with epoxy resin. This complex production process makes it particularly easy to cut the colour backgrounds to size whilst providing an extremely tough, colourfast surface.

  • Are JUWEL decorative items suitable for saltwater?

    All decorative items from JUWEL Aquarium are suitable for saltwater.

  • What is the correct way to cut JUWEL backgrounds and filter covers to size?

    Filter covers can be cut precisely to size using the enclosed template. Backgrounds must be cut to the dimensions of the aquarium.

  • What tool do I use to cut JUWEL backgrounds and filter covers?

    All backgrounds and filter covers can be cut with a standard Stanley knife.



  • What guarantee comes with my JUWEL Aquarium?

    We guarantee all of our products for 2 years from the date of purchase. Filter sponges and fluorescent tubes as well as all components that are subject to normal wear, e.g. the impeller of the pump, are excluded from the guarantee. Any guarantee claim must be substantiated with a valid proof of purchase.