These bulbs are the small singular bulbs you can buy at every pet store. They look like the eco-friendly bulbs you can buy for your home. They are commonly used for reptiles since they are cheaper than MVB bulbs or tube UVB bulbs. These bulbs may be unknowingly harming your reptile. Here are the reasons these bulbs are dangerous for your animal.
Compact and coil UVB bulbs have been known to cause serious and sometimes fatal burns. This can be from different reasons; one reason is the bulb is physically too close to your dragon. But all bulbs have a distance chart to help you with that. Another reason that is unavoidable is they emit low wavelength UVB.
They have also been known to not have enough UVB, increasing the risk of MBD (metabolic bone disease, lack of UVB and calcium). Some 3rd party studies have been done and show they will sometimes emit half of what they claim to emit. Meaning they will lose UVB faster. Most people use the rule of changing them every 6 months, but not realising the UVB is most likely completely gone and your dragon is not getting any UVB. Even a few weeks without proper UVB will take its toll.
Lethargy, constipation, improper weight and illness
Lethargy: Many owners have reported their dragons being lethargic; this can be from insufficient UVB. With lack of UVB comes with many symptoms, including; droopy eyes, laziness, twitching of body parts & illness.
Constipation: Constipation can be from lack of UVB; since they need UVB to absorb D3, they will be all out of balance without it. Although constipation is usually caused by improper temperature and diet, sometimes getting better UVB for your dragon will help.
Improper size: Lack of UVB can alter the size of your dragon, especially younger dragons (it is essential for proper growth). So giving them the best UVB available is very important.
Illness: Many serious illnesses are caused by lack of UVB, such as; MBD, mouth rot & seizures. As you probably already know, UVB is essential for beardies to live. Without it, no matter how much heat or food you provide, they will die.
Here is a study done on some of the bulbs, with reports of burns and even deaths:
Although the study was done in 2008 there are still countless numbers of illnesses and even deaths. I personally have seen the devastating results of using these kinds of bulbs. Even if the bulbs improve dramatically, the beam is too small. UVB should be spread across most of the cage.
What should I use instead?
There are a few UVB options available, these include: MVB's (Mercury Vapor Bulbs) are all-in-one bulbs that also provide UVA, UVB and heat. Tube UVB bulbs (long fluorescent bulbs) are also an option, they are my personal favourites. Tubes will cover more than half of the tank making sure they receive optimal UVB throughout the enclosure (as opposed to one side of the tank).