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Common issues T5 tubes & Halides and simple fixes

Date Published - 29th May 2014 - Published by - iQuatics Ltd

Common issues T5 tubes & Halides and simple fixes

There are a few common issues T5 tubes & halides can throw up that are easily fixed.
My T5 tube isn’t lighting up correctly or I can hear a rattle inside the tube is there a fault? 
This is a question we get asked quite frequently here at iQuatics so we thought we would write a little something on how a T5 works and what the answers to these questions are. These are common issues T5 & Halides can give you but are easily rectifiable.

Let’s start off with the basics, a T5 tube in all reality is a simple but of kit. There is very little that can go wrong with them, granted every now and then there will be a tube that for no reason just won’t lignite but on the whole, unless they are damaged in some way there is normally a simple explanation for most things that occur with them.
My tube is rattling, is something broken? 
The short answer to this question is no. It is perfectly normal to hear a rattle inside the tube, inside each tube is a small mercury ball, this ball is what excites the phosphors when an electrical current is passed through the tube, basically this ball is what causes your T5 tube to ignite.
My tube is not lighting up correctly, or is dull on one side?
When this happens again I have to refer you back to our friend the mercury ball! If the ball becomes trapped within the filament at either end of the tube it takes longer for it to work its magic, given time the tube will in 99% of cases ignite fully any way but to speed up this process and get things running 100% it’s simply a case of giving the tube a good shake until you hear the ball rattling inside, pop the tube back in and you should have a T5 working at 100%
If your using a T5 controller, and you left the tube ignited and tilted the tube from the light side to the dark side you can normally visually see the dark side of the tube light up as the ball rolls free, however we would always recommend that tubes are disconnected from the electrical supply before attempting to release the ball.
I’ve received my order and non of the T5’s are working?
In this situation we would always then look at the ballast first, the chances of receiving 3 or more T5 tubes, in the same order that are all faulty is less likely to happen than winning the lottery ! Most ballasts in aquarium equipment are twin ballasts, they run the tubes in series, so this means that if they go it will take out all of the lighting on that series.
I’ve received my halides and they don’t work , I’ve put my old bulbs back in and they work fine?
Again another problem we encounter frequently, and again an issue that isn’t down to the bulbs ! Inside your halide unit there are numerous components that make the bulbs work, you have a ballast, a capacitor and an igniter, in this situation it is usually the igniter or the capacitor that is causing you your problem. It takes far more electrical energy in the first instance to ignite a brand new halide than your old bulb that you have had running for 9 months +.
You will often find that a small blue line of electricity can be seen within the bulb, this demonstrates that power is being received to the bulb but there isn’t enough to “push” the ignition process.
We hope this has gone someway to answering some of your questions as always though if you are unsure or would like any further help with your aquarium lighting then please give us a call on 0845 269 7417 or drop us an email to
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