Juwel light units are undoubtedly a popular choice for high quality aquarium light. So here's everything you need to know to keep your Juwel light units working at their best, as well as some helpful hints and tips for when they fail.
How reliable are Juwel light units?
We sell thousands of Juwel light units and Juwel aquariums containing these lights every year. Our customers have units of all sizes, ranging from the older Juwel T8 units, which Juwel has now discontinued, to the more modern Juwel High Lite T5s, and the overall fault rate for both types is very low.
Juwel light units are really reliable in general and can go on for years without any problems. However, there are a couple of things that can cause them to stop working. Due to the popularity of Juwel aquariums and the volume we sell, they are also among our most frequently returned products and we get a few sent back every week. However, the vast majority aren't actually faulty!
Why is my Juwel light unit not working?
We reckon that around 70-80% of all Juwel light units we see returned are actually fully functional - they just need new bulbs fitting. If you come home one day to find your Juwel light unit not working there's a strong possibility it's simply that the bulbs have blown.
Juwel light units typically contain two T5 or T8 fluorescent lamps, and if one or both of them blows - which they can do after 12 months or so - neither of the bulbs will light up. This leads the customer to believe the entire light unit is faulty, when really it's just the fluorescent tube that's blown.
The customer has to go to the hassle of calling us and booking a return, when there's nothing technically wrong with the item at all. We need to test every unit returned to us - particularly given the high number of products returned which aren't actually faulty. So customers can be without their light for no reason for a week or more. Although it doesn't really cause any major problems for the livestock, this is an inconvenience most aquarium owners would rather be without.
It's also really expensive for us, since we cover all costs for the customer. We pay around £10 for the item to be collected from the customer, and £5 to return it, and need to employ specialist staff to handle the returns.
What else can be the cause of a faulty Juwel light?
There are two really common things. The first is simply that the fuse has blown in the plug. This is something that can happen to any electrical appliance and it's easily fixed by non-electricians for under a pound, with no need to return the product to us.
The second is that the socket or extension that the light unit is plugged into has developed a fault. It's really common for the returned Juwel light units, and other electrical appliances we get returned, to work instantly as soon as they're plugged in, but for the customer to claim upon its return that it still doesn't work, only later to find that it was their plug socket or extension cable which was at fault. As a result, we always recommend that customers plug the lamp into another socket they know to work to see whether it works in that.
Which replacement Juwel bulbs do I need for my unit?
Firstly, you need to make sure that you pick the right replacement bulbs for your Juwel light unit. Juwel aquariums all include Multilux lighting. In newer models these are generally Juwel High Lite light units, which take narrow Juwel T5 light tubes. In older models, and those at the bottom end of the Juwel range, they are Juwel T8 bulbs. It's easy to tell the difference: Juwel T8 bulbs are 1" in diameter, while Juwel T5 bulbs are 0.5" in diameter.
Like other fluorescent bulbs, Juwel light bulbs are sold by wattage and length - you'll need to know both to pick the right one for your Juwel aquarium.
The 55cm/24 Watt bulb will work in the Juwel Trigon 350, Juwel Delta 80 and Juwel Lido 100. The 60cm/24 Watt bulb is for the Juwel Lido 120. The 70cm/28 Watt bulb fits the Juwel Trigon 190, Juwel Delta 100 and Juwel Delta 300. While the 80cm/28 Watt bulb is for the Juwel Rio 125 and Juwel Panorama 80.
Of the larger bulbs, the 92cm/35 Watt fits only the Juwel Vision 180. The 100cm/45 Watt bulb fits the Rio 180, Panorama 100, Trigon 350 and Delta 300. The 120cm/54 Watt bulb fits this Juwel Rio 240, Juwel Rio 300 and Juwel Panorama 200, while the largest bulb, the 150cm/54 Watt fits either the Juwel Rio 400 or the Juwel Rio 450.
Juwel High Lite bulbs also come in several colours. The Juwel High Lite Day bulbs are bright lamps designed to stimulate plant growth in tropical freshwater or coldwater aquariums; Juwel High Lite Nature bulbs produce a warmer, less bright light also designed for plant growth; Juwel High Lite Colour bulbs help emphasise red and blue colours in fish, while Juwel High Lite Marine are designed for general marine aquarium use, and the Juwel High Lite Blue is an actinic blue light designed for corals and other photosynthetic inverts.
How do I pick the right replacement Juwel lighting?
If your unit is out of warranty and you are looking for replacement Juwel lighting you simply need to select the same replacement light unit as the one you already have. If you have an older Juwel aquarium, it's also possible to upgrade to the newer Juwel High Lite T5 light unit, which will provide better lighting and a wider range of bulbs.
Juwel made its light bulbs a different length to the standard T5s used by other manufacturers, so you'll need to buy official Juwel T5s to install in your unit. Standard T5 bulbs won't fit.
How do I install new Juwel light bulbs?
It's very easy to install new Juwel light bulbs. However, if you don't install them correctly they may not light up and water could get into the light unit, which could damage it irrepairably. Juwel recommends that you always replace both bulbs at the same time, rather than just replacing one. This is a good idea, because it's difficult to tell which bulb has blown since the unit won't work with only one working bulb.
Firstly, you'll need to unplug the light unit from the mains to make it safe to work on. Don't just switch it off, actually pull out the plug! Carefully unscrew the white lamp holder at each end and slide it along the tube. Then, carefully remove the tube by pulling it towards you. It sometimes takes a wiggle to get it out.
Slide off the end caps from the old tube, unbox the new tube and slide on the end caps. Align the pins on the end of the bulb with the holes in the lamp fitting, then push it into place until it clicks. If it doesn't get seated properly there won't be an electrical connection and the bulb won't work. Slide the end caps down and firmly tighten them up.
Make sure your hands are dry, then plug the Juwel light unit back in and turn on the power. The bulbs should light up when the switch is turned on. If they don't, double-check that you've replaced both bulbs (a single faulty bulb will cause the entire unit to stop working) and that the pins are correctly seated. If this doesn't work, check the fuse and then the plug socket to make sure they're not at fault.
How can I determine whether my Juwel light unit is faulty?
If your Juwel light unit is not working, here are the steps we'd recommend taking to ensure it's faulty before sending it back for repair or replacement.
1. Re-install the bulbs
Juwel recommends that you first try re-seating the original bulbs if your unit fails to turn on. Unplug the unit from the mains and remove it from the aquarium. Unscrew the end caps and slide them along the bulb then carefully remove and reinstall each bulb, screw the caps back down and plug it in. If that doesn't work, try step 2.
2. Install new Juwel light bulbs
The most common reason for a Juwel light unit to stop working is because one or both of the fluorescent tubes have blown. Try replacing these first, particularly if the bulbs are 12 months old. Darkening at the end of the bulb is a good sign that it's on the way out...
3. Plug the Juwel light unit into another socket
Faulty plug sockets and extensions are another big problem. To confirm that the problem doesn't lie with your plug socket or extension lead, plug the light unit into another socket that definitely works.
4. Change the fuse on your plug
Change the fuse in the plug of your Juwel light unit. Make sure you replace it carefully and use a fuse of the correct size.
What happens if the ballast fails?
The ballast in a Juwel light unit is inside the sealed part of the unit as it needs to be protected from water getting to it. If this part goes wrong, unfortunately the unit can't be repaired and you'll need to replace the entire unit. Water rarely gets inside Juwel light units, unless the user hasn't installed the bulbs correctly and the waterproof seals at the ends of the bulbs aren't fitted snugly.
When this happens the unit will usually just trip your circuit breaker, so tripping is generally a sign that the unit is wet due to incorrectly seated bulb seals.
There are some guides on fishkeeping forums which show how some users have cut open their Juwel light units with a Dremmel and replaced the ballast, however, although this may result in a functional light, it's potentially dangerous and we highly recommend you do not attempt it!
How long are they guaranteed for?
Juwel light units are guaranteed for two years from the date of purchase. The guarantee only covers the unit itself, and not the bulbs which are disposable items (like the tyres on a car) and need replacing every 12 months or so. If the unit develops a fault within two years, and you've confirmed it's definitely not the bulbs, the plug fuse or your socket or extension, you can return the unit to the place you purchased it from under warranty.
How do I return a faulty unit to you for repair or replacement?
If you've tried fitting new Juwel light bulbs (the entire unit will fail to work if just one of the bulbs has blown), have fitted a new fuse, and have tested the light unit in a socket you know to work, please give us a call to arrange a return. We'll check whether the item is in warranty and help you get it sorted.
We will cover the cost of collecting the light unit from you and the cost of returning it. You won't even need to go to the Post Office as we'll pay for the item to be picked up from your door. You will need to find a suitable box for your light unit and pack it very securely to prevent it being damaged in transit. You'll also need to include a sheet of paper inside which explains what the fault is and who it was returned by.
There's no need to affix a label to the box, since the courier will add a pre-printed label to the box when he collects the parcel from you. However, don't forget to put your name and address on the outside so we know who the return is from.
How often should the bulbs be replaced?
The bulbs can continue to work for well over 12 months, but the useful light they emit starts to drop by the time they're about a year old, so they become less useful for growing plants and corals, and some say they may even start to encourage the growth of algae. As a result, most experts recommend changing the bulbs every 12 months to keep the light spectrum and intensity produced at the optimum level.