Turtle Basking Light Guide for Absolute Beginners

Turtle Basking Light Guide

The information is current and up-to-date in accordance with the latest veterinarian research.

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Lighting is one of the most important and basic concepts of a turtle tank. Like feeding and basking, lighting is also an essential requirement for a healthy turtle.

I have seen that the thing that confuses most of the beginners is the lighting. So, in this article, I am going to write a complete turtle basking light guide for all the beginners. This guide should answer all your problems regarding basking light for turtles.

key takeaways

  • Turtles need both UVB and heat lamps in their tank to mimic natural sunlight for healthy shell growth and bone density.
  • The UVB light is crucial for vitamin D3 production, essential for the turtle’s shell growth and digestion.
  • Heat lamps provide necessary warmth for turtles, as they are cold-blooded and rely on external heat sources.
  • Proper lighting is vital for maintaining turtles’ circadian rhythm, influencing their stress levels and immunity.
  • UVB lamps should be replaced every six months as their efficiency diminishes over time.
  • Turtles require a day-night cycle; constant light can disrupt their natural behaviors and health.
  • Mercury Vapor Lamps are an option, providing both UVB and heat, but they consume more energy.
  • It’s important to measure and maintain correct temperatures in the tank for the health of the turtle.

why proper lighting is a must for turtles?

Lighting in a turtle tank isn’t mean only for us so that we can see the turtles. lighting is extremely important for the healthy shell growth and bone density of turtles. In the wild, aquatic turtles receive vitamin D3 from the sun while they are basking.

As in indoor setup, they can’t get any sunlight, we need to provide them proper lighting. This proper lighting includes both a UVB light and a heat lamp.

The UVB light emits UVB ray which contains vitamin D3, which is essential for the turtle’s shell growth and digestion.

The heat lamp provides the essential heat that is needed for basking. Basically, these two lights imitate the sun on the outside. Your turtle needs both vitamin D3 and enough heat to thrive.

What type of lights does turtle need?

Basically, you need to imitate the sun inside the turtle tank. Turtle gets UVB ray and heat from the sun in the wild. So, you’ll need two types of light: a UVB light and a heat lamp.

UVB lamp

As the name implies, the UVB lamp provides the essential UVB ray for the turtles.

The UVB ray is essential for producing vitamin D3 which promotes healthy shell and bone growth in turtles.

The UVB also encourages activity, feeding, mood as well as breeding.

Heat lamp

Like the sun provides heat to the turtles in wild, the heat lamp does exactly the same. It produces warmth for the turtles.

As turtles are cold-blooded animals, they can’t generate their own heat. So, they need to depend on other sources for maintaining body temperature. The heat lamp helps to do this. It also helps to fight germs.

Without proper lighting, most aquatic turtles will get sick in a very short time and at worst cases, they may die from metabolic bone diseases. Like all living animals, turtles also maintain a circadian rhythm. Which means, they need day and night in a 24-hour cycle just like us.

Without a day-night cycle, the daily habit of your turtle will be disrupted, it will cause stress and reduce the immunity of your turtle. So, lights are extremely important for turtles.

Turtle Basking: Why, When, How? [Infographic]

If you want a printable version of this PDF, click here. Please link back to this source if you use the infographic on any other website!

Recent research has found that nocturnal basking is more widespread among freshwater turtle species than previously thought. A global assessment published in 2023 showed that at least 29 freshwater turtle species from seven families have been observed basking at night (source: ScienceDirect).

Why turtles need UVB?

  • Turtles, including all reptiles, need UVB to produce vitamin D3 in their bodies. It also helps them to properly digest food and get calcium.
  • Vitamin D3 is responsible for healthy shell and bone growth. So, in the absence of UVB light, the turtle may suffer from metabolic bone diseases and other shell issues. At worst, this disease can cause death to turtles.
  • UVB ray is essential for digesting food. Without a proper UVB light, many baby turtles can die within only a year.

Many turtle owners come to me and say their turtle died suddenly. In most of the cases, they didn’t have any UVB light in the setup.

Things to consider when getting a UVB light

Research is Key:

Don’t rely solely on the knowledge of the salesman when purchasing items for your turtle. Many turtle sellers lack awareness about the necessity of UVB light for turtles. Always conduct your own research before acquiring a UVB light.

Understanding Labels:

The terms “Full-Spectrum” or “Sun-Spectrum” on bulb packages don’t guarantee UVB content. In fact, most full-spectrum lights contain only a negligible amount of UVB.

Be cautious and don’t be misled by these labels.

UVB Lamp Lifespan:

UVB lamps have a limited effective period. While they may continue to emit light, their UVB output significantly diminishes after about six months. Hence, it’s crucial to replace the UVB bulb every six months.

Choosing the Right UVB Lamp:

There are various types of UVB lamps available. For turtles, experts typically recommend 2.5, 3, or 5 percent UVB lamps, often referred to as tropical UVB lamps, which are ideal for turtles. Conversely, 10 percent UVB lamps, known as Desert UVBs, are not suitable for aquatic turtles.

If necessary, a 10 percent UVB lamp can be used temporarily by positioning it further from the basking area until a tropical UVB lamp is obtained.

Proper Placement:

The placement of the UVB lamp is crucial for ensuring the turtle receives the right amount of UVB. For a 2.5 percent UVB lamp, maintain a distance of about 12 inches. If using a 5 percent UVB lamp, it should be placed at least 18 inches away from the basking light.

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UVB Transmission Issues:

UVB rays cannot penetrate plastic or glass. If your turtle habitat is covered with glass or plastic, most of the UVB will be absorbed. Use a metal screen cover with large holes to avoid significant UVB loss.

Safety Precautions for Hot Lamps:

If your UVB lamp generates heat, place a mesh screen below it to prevent accidents. Lamps like halogen, mercury vapor, or incandescent can shatter upon contact with water, posing a risk to your turtle. LEDs and fluorescents are safer alternatives as they are less likely to break or overheat.

Lighting Guide For Turtle Keepers: Infographic

If you want a printable version of this PDF, click here.

Some turtle species have even been seen basking near sources of light like crocodiles at night (source: National Geographic). This suggests that artificial lights may also attract turtles looking to bask after dark.

suggestion from a turtle expert

Understanding the lighting needs for a turtle tank can be daunting for beginners. Self-Ballasted Mercury Vapor Lamps, which have recently become more affordable, are an all-in-one solution, offering daylight, heat, UVA, and UVB.

Bradfield Johnson, a seasoned reptile hobbyist, recommends a combination approach for optimal turtle care.

He suggests using a Reptisun T5HO strip UV for wide UV distribution, complemented by compact UVB bulbs and at least two heat/basking bulbs, like Arcadia or Mixjoy, for UVA with heat.

Emphasizing the importance of a large enclosure for microclimates, Johnson also highlights the critical role of water quality and robust filtration, recommending Fluval’s FX-6 filters for aquatic setups.

Can you use a Mercury Vapor Lamp for turtles?

Mercury Vapor Lamp for turtles

I know I have told earlier that you need at least two types of lights for your turtle tank: a UVB light and a heat lamp.

However, there is a type of light that can replace both of these lights. In fact, all of the turtle’s requirements will be fulfilled with only this light alone.

This is the Self-Ballasted Mercury Vapor Lamp.

Self-Ballasted Mercury Vapor Lamps provide daylight, heat, UVA, and UVB simultaneously.

Owners who don’t have enough room on their turtle habitat or want to get only one light, this can be an excellent choice.

In the recent years, the price has gone down too! Most turtle owners love them because they replace the need of using two types of lights.

However, Mercury Vapor Lamps come with some disadvantages too. Here are the downsides of these lights:

  • Mercury vapor lamps consume more electrical energy than a typical fluorescent UVB lamp or a halogen basking light.
  • In fact, a recent study found that these lights consume twice more energy than a normal light.
  • As these lights consume unbelievably more energy than normal basking lights, the electricity bill can go through the roof, especially if you live in an area where the electricity cost is high.

Different types of UVB lights:

linear vs tubular uvb bulb

There are basically two types of UVB lights in the market right now: The Linear or tubular light and the Compact UVB light. Most turtle owners these days often go for the compact UVB lights.

The compact UVB bulbs are squiggly shaped. You need to screw them into the socket. When these bulbs first came out, they weren’t very reliable. Some bulbs produced no UVB where some produced more than the specified amount of UVB.

However, the manufacturers redesigned these bulbs and now they are the most popular choice for turtle owners. However, that doesn’t mean tubular UVB lights are obsolete. Some turtle owners prefer the tubular ones than the other.

If you do choose a compact style UVB bulb, I’ll strongly recommend not to use a mirror style reflector with it. It will over concentrate the UVB onto the basking area. You can go for a metal or white painted interior with the compact UVB bulb.

If the bulb is too much powerful, your turtle will show eye irritation. If you observe any type of irritation in your turtle’s eye, turn off the light immediately and wait for a few days before you turn it back on.

Just because a UVB lamp is lighting up doesn’t necessarily mean that it is producing enough UVB. So, you need to replace the UVB bulbs at 6 months or 1-year interval, depending on the bulb.

Here is a table comparing different types of lights for turtles, including their key specifications and features:

Type of LightTemperature OutputBulb LifeEnergy UsageUVB OutputPrice Range
IncandescentModerate to High750 – 1,000 hoursHighLow$
Mercury VaporVery High6,000 – 10,000 hoursModerate to HighHigh$$$
FluorescentLow7,000 – 15,000 hoursLowModerate$$
HalogenHigh2,000 – 4,000 hoursModerateLow$$
LEDLow to Moderate25,000 – 50,000 hoursVery LowVariable$$
Owner: Sarah Miller

Heat Lamps:

Heat lamps, also known as the daylight lamps, are also essential for a turtle’s healthy growth. Heat lamps produce light and heat at the same time. Incandescent lamps are a popular choice for heat lamps.

There are also halogen heat lamps. Some of these lights come with reflectors to increase the concentration of the heat.

The heat lamp should be directed to the basking area at a perfect distance.

Set up the lamp in such a way that the temperature of the basking area is at least 10-12 degrees warmer than the temperature of the water.

The warmest part of the basking area should have a temperature between 85 to 90 degrees Fahrenheit. You can increase the range to about 95 degrees Fahrenheit if the turtle is sick.

The perfect way to set up the heat lamp is to make a nice temperature range in the basking area. This way, the turtle will choose its preferred temperature. The warmest part of the basking area should be the high end of the temperature range.

On the other hand, the coolest part will indicate the low end of the range. This way, the turtle can regulate its body temperature easily by moving on the basking area. That’s why you need to buy a bigger basking area for your turtle.

How to measure the temperature?

Never ever try to guess the temperature of your turtle habitat. Temperature is a very crucial thing for turtles. You need to know the exact temperature of the water and the basking area. That’s why I always recommend using a reptile oriented thermometer for your turtle tank.

I love zoo med’s reptile thermometer. I have been using them for years and they never gave me wrong results. Granted that they can be a little overpriced than other thermometers, however, I don’t want to risk getting a cheap low-quality thermometer which can essentially put my turtle’s life into danger.

When measuring the temperature, do not remove the cover of the turtle tank (if you have any). Covers can control how much light and heat are entering into the turtle habitat. So, removing them will give you a false reading on the thermometer.

See also  Zoo Med Aquatic Turtle UVB and Heat Lighting Kit Review: Do you need it?

“Safety Precautions” for us:

When we are handling with lightings for turtle, we need to take some precautions beforehand. Here are the safety precautions we need to take:

  • Never ever look directly at the lights. These lights are very powerful and can permanently damage your eyes.
  • UVB lamps are more dangerous than the heat lamps. If stared directly into those for a long time, you can get permanent blindness.
  • Also, ensure that there is nothing in the room that reflects the UVB ray directly into peoples’ eyes.
  • Make sure that you have tightly secured the bulbs in the socket. They should never fell off in the water. Such accidents can get your turtle electrocuted.
  • That’s why I like to use a mesh cover on my turtle habitat. It works as a protection if by any chance my lamps fall from the sockets.
  • The final rule is to never work with turtle lights (or any other electric instruments) when they are ON. Always remember to turn OFF before you need to do anything.
  • Also, make sure you don’t splash any water on the bulbs as water splashes can shatter the glass of the bulbs.

A viewing light:

viewing light for turtles

I wouldn’t recommend getting a light for viewing unless you have a very big habitat. These viewing lights do not have any special purposes like UVB, heat etc. They are just for viewing the turtle tank. In other words, the viewing lights are for us, not for the turtles.

I like daylight lamps for viewing purposes. They are better than soft white or warm white lights. Plants also prefer the daylight lamps more. Daylight lamps are available in many shapes. I like the LEDs as they are very cheap and practically last forever.

You don’t need to go over any technical details when choosing a daylight lamp for turtles. just make sure the spectrum is between 5000k to 6500k.

If you do decide to use a daylight lamp, turn it ON and OFF at the same time with the UVB lamp and the heat lamp to maintain the Circadian Rhythm of your turtles.

Night Lights:

Night Lights for turtles

I have also seen many people using night lights on their turtle tank. It is not a requirement at all. You can only get one if you want to observe what your turtles are doing at night.

Night lamps are basically dim lights with very low intensity. They are generally red or blueish and produces very soft light that does not irritate the turtle’s eyes.

In some cases, night lights are good for hatchlings as they produce some heat throughout the night. Moreover, most hatchlings sleep on the warmest part of the basking area.

Adult turtles don’t care about night lights at all. They don’t care if it is blue or red. However, some owners said that their turtles didn’t really go with the red one. So, I prefer to use blue night lamps for my turtle tank.

I have also seen many owners using an infrared heat lamp as night lamps.

These lights produce a red light with mild heat which is very good for new-born hatchlings. Infrared heat lamps are also effective for sick turtles as the heat helps the turtles to fight the germs.

When choosing a night light for your turtle tank, make sure that the light only turns ON when all the daytime lights (UVB light, heat lamp, and viewing light) are turned OFF. If all are ON at the same time, your turtle can get burnt. Also, ensure the night lamp isn’t producing too much heat that can make the habitat unbearable for your turtles.

Need To Talk With A Turtle Vet Right Now?

Circadian Rhythm

automatic timer for turtle tank

If you don’t know what Circadian Rhythm is, it is just a scientific term of the 24-hour cycle of each living animals. Like most living animals, turtles also maintain a circadian rhythm.

Throughout the 24-hour cycle, they focus their energy on different things at different times. Not only the behaviors, their biochemistry also change throughout the 24 hours, thus maintaining a specific circadian rhythm.

It’s extremely important that we maintain a day-night cycle in our turtle tank, much like in the wild. The day-night cycle is crucial for the healthy growth of every turtle.

If you keep turtles in an outside pond, then you don’t have to worry about any of this. However, those of us who keep their turtles in an indoor habitat, we need to mimic the sun to create an artificial day and night environment.

We should maintain an 8 to 10-hour day cycle in the tank. During the daytime, keep the UVB lamp, heat lamp and the viewing light (if you have any) ON. During the night time, only keep the nightlight ON (if you have any). It is okay to have no light during the night too.

It is not easy to maintain a precise daytime and nighttime every day manually. That’s why I strongly encourage everyone to get an automatic timer. An automatic timer will be an excellent investment for your turtle tank. They don’t cost much and take all the manual work out for maintaining the circadian rhythm. All you need to do is program the timer and turn it ON. The timer will do the rest.

Zoo Med UVB and Heat Lighting Kit:

Zoo Med UVB and Heat Lighting Kit

Zoo Med is a popular brand across the USA for their large selection of high-quality reptile and amphibian products.

Zoo Med has made the life of hundreds of turtle keepers easy and convenient with its reliable, cost-effective products.

Zoo med’s UVB and heat lighting kit is a 2 in 1 lighting fixture which provides maximum convenience to the turtle owners. The dual fixture feature allows using both the UVB lamp and the heat lamp under one polished aluminum dome.

Zoo med’s UVB and heat lighting kit saves both time, space and money. You don’t need to buy all the lighting items separately. It also saves a ton of space on your turtle habitat.

I used zoo med’s hundreds of products and almost all of them satisfied me. This lighting kit is not an exception either. Comparing with other similar products in the market, I think thus UVB and heat lighting kit provide the most features at the cheapest rate.

With the lighting kit, you’ll also get a 13-watt ReptiSun UVB 5.0 bulb (Mini Compact Fluorescent version) and a water splash proof 50-watt halogen lamp for heat. T

his is basically an All-In-One lighting solution for turtle tanks. These bulbs are also very low power consuming. So, you won’t see a huge jump on your electricity bills.


  • The lighting kit has a polished aluminum dome which works as an excellent reflector. It increases the light as well as UVB output by 30%.
  • The fixture has dual sockets to use both lights at the same time. You can use up to 100 watts of light at each socket simultaneously.
  • The sidewalls of the dome extend beyond the size of the bulbs. So, the bulbs are protected from any kind of water splash from the outside. It also helps to prevent “sticking out” of the bulbs.
  • You’ll get 1-year warranty with the UVB and heat lighting kit.
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  • The dimension of the kit is about 9.4 x 12.4 x 3 inches.
  • It weighs about 2.35 pounds.

Keep in mind that, you must need to replace both of the bulbs every six months. After a six month period, the UVB bulb starts to degrade and just become a normal light.

So, you must replace the old one with a new UVB bulb. This is very important. You can place a mark on the calendar or make a reminder on your phone so that you don’t forget to change the UVB bulb.

Is It Safe To Leave A Reptile Heat Lamp On All Day?

Turtles are diurnal creatures, which means their activities depend on the night and day cycle. During the day, these animals are most active, while they sleep through the night.

But it is tough for an indoor turtle to gauge the day and night hours. So, they are totally dependent on artificial lights. For example, a heating lamp acts as the sun and provides them with heat to conduct their daily routine.

Likewise, when you turn the heating lamp off, it cools off the pen. Hence, the turtles take it as a night and go to sleep.

It is why professionals advise keeping the heating lights on for 12 hours during the day. You should switch off the lamp during the night to replicate the day and night cycle.

So, leaving the reptile heating lamp all day and night is unsafe. It will disrupt the biological clock cycle of turtles.

However, the vets may sometimes suggest keeping the heating lamp on for extended hours. The reason can be a severe cold or a respiratory infection in the pets.

How Long Do Reptile Heat Lamps Last?

Quality reptile heating lamps offer a generous lifespan. For example, using the light in the right setting will last over a year. However, there are also claims the heating bulbs could not fit for 3 months.

Do Turtles Need Light 24 Hours A Day?

As explained, lights influence the circadian rhythm of turtles. It means the creatures understand the difference between day and night utilizing lights.

Just like in the wild, 10 – 12 hours of daylight or artificial heating light is enough for them. Keeping the light on 24/7 will disrupt the turtle’s sleep cycle and health.

Do Turtles Need Light At Night?

Turtles need to experience the entire day and night cycle to function properly. While a warm temperature is necessary for the daytime, a chill environment helps the turtles sleep during the night.

With a heating lamp on at night, turtles can not enjoy their sleep anyway. Besides, the brightness will irritate the turtle’s eyes.

So, it is a big no to night lights for turtles.

Yet, some owners install night lights in the turtle pen to observe the pet 24/7. If you plan to buy one, go for the special night lights for reptiles.

The night lights come in blue and red, with low intensity and brightness. Infrared light is also a good idea for hatchings.

How Long Should I Leave My UVB Light On For My Turtle?

8 – 10 hours of UVB rays is enough for the healthy development of the turtles. Depending on your geography, you may want to keep the lights on for 12 hours. Turtles use UVB and a heat lamp to keep up with their circadian cycle.

Do Baby Turtles Need A Heat Lamp?

A heating lamp is essential for turtles of all ages, especially babies and sick ones. The hatchlings are weak and vulnerable during their first year. They need proper light and UVB to build up their health and immunity.

As per reports, hatchings with inadequate UVB can not survive a year.

Hence, you need to install a heating lamp in the baby turtle’s pen. If it is cold, keep the lights on for 1/2 extra hours. Moreover, set up an infrared light for additional warmth at night.

How Much UVB Does A Turtle Need?

UV lamps with 2.5 – 5% UVB are fine for aquatic and semi-aquatic turtles. Lights with 10% UVB are also available, but those perfect are for tortoises.

Besides the correct percentage, you must also focus on the installation distance. The ideal distance of the UV lamp and basking dock are 12 inches and 18 inches for 2.5% and 5%, respectively.

How Far Should Basking Light Be From Turtle?

Distance between the basking light and the dock definitely matters. If you install the lamp too close, it will create a burning hot environment. Again, the light can cause fire when the habitat includes wood chips or shavings.

The ideal distance chart between the basking light from the turtle is,

Bulb PowerDistance From Turle/ Basking Dock
50 watt5 – 7 inches
75 watt7 – 9 inches
100 watt10 -12 inches
150 wattMore than 12 inches

Frequently Asked Questions

How long should a turtle basking light be ON?

You should maintain the day-night cycle in your turtle tank. So, depending on where you live, you can keep the daylights (UVB bulb, heat lamp, and viewing lamp) ON for 8 to 10 hours per day. All the daylights should be turned ON and turned OFF at the same time.

Do turtles need a heat lamp at night?

No, turtles generally don’t need any kind of light at night. The night is for sleeping and resting. However, you do need to have a heat lamp during the day cycle of your turtle tank.

Do baby turtles need light at night?

It is not an absolute necessity for baby turtles to have lights at night. However, it is better if you can get a soft night light for baby turtles. The night light will produce a mild heat throughout the night, which is good for a baby turtle’s health.

Do red-eared sliders need a night light?

Most aquatic turtles, including red-eared sliders, do not care about any night light. So, there is no necessity for getting night lights for red-eared sliders. However, if you have a baby red-eared slider, then it can get benefitted from a night light.

What is the preferred turtle basking lamp distance?

The distance depends on the intensity of the UVB bulb. If you have a 2.5 percent UVB bulb, then keep the bulb at a 12-inch distance from the basking area. For a 5 percent UVB bulb, the preferred distance is 18 inches.

What is the preferred turtle heat lamp wattage?

There is no preferred wattage of heat lamp for turtles. What we need is the preferred temperature. Make sure that the basking area is at least 10 degrees warmer than the water. An ideal temperature range of the basking area should be between 85 to 90 degrees Fahrenheit. So, set the heat lamp in such a way that it can create such temperature range in the basking area.

Do turtles need heat lamp all the time?

No, you’ll need to turn ON the heat lamp during the day-cycle only. So, if you are aiming for a 10-hour day cycle, then keep the heat lamp turned ON for 10 hours along with the UVB bulb.

Is it safe to leave the heat lamp ON all day?

No, it is not safe and recommended at all to leave the heat lamp ON for all day. The temperature can get really high and it can burn your turtles. Also, keeping the heat lamp ON all day may result in irritation on your turtle’s eyes.

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About Author

Muntaseer Rahman started keeping pet turtles back in 2013. He also owns the largest Turtle & Tortoise Facebook community in Bangladesh. These days he is mostly active on Facebook.


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