Solarmeter® Model 6.5R Reptile UV Index Meter
Solarmeter’s new Model 6.5R Reptile UV Index Meter updates our legendary original Model 6.5 UV Index Meter with attractive, informative graphics specifically designed for reptile husbandry. Many scientists and breeders worldwide rely on the original Model 6.5 UV Index Meter, so the new Model 6.5R is unchanged operationally or in terms of specifications from the original. We just made this meter easier for reptile owners to use by updating the graphics with the latest scientific research about proper UV dosages for reptiles.
Solarmeter’s new Model 6.5R Reptile UV Index Meter updates our legendary original Model 6.5 UV Index Meter with attractive, informative graphics specifically designed for reptile husbandry. Many scientists and breeders worldwide rely on the original Model 6.5 UV Index Meter, so the new Model 6.5R is unchanged operationally or in terms of specifications from the original. We just made this meter easier for reptile owners to use by updating the graphics with the latest scientific research about proper UV dosages for reptiles. Specifically, the Ferguson Zone chart at the top of the meter provides the user with an instant, accurate reference for the meter’s UVI readout.
Meter Operation
To operate your Solarmeter, aim the sensor window located on the top panel of the meter directly at a UV source. Press and hold the push-button switch on the face of the meter. For best results take note of the distance the reading was taken from the UV source in order to ensure repeatable results. Battery operation voltage is viable from 9V down to 6.5V. Below 6.5V, the numbers on the LCD display will begin to dim, indicating the need for battery replacement. Under typical service load, a standard 9V battery will last approximately 2 years.
Proper Usage of Solarmeter® Ultraviolet Radiometer
Wear eye protection when checking UV lamps (Glasses that provide wrap around protection are ideal). Allow lamps to warm up prior to taking readings (at least 15 minutes).
SOLARMETER MODEL 6.5R UVI READOUT
Note: Data is shown in two basic sets of values with two ways of providing UV: “Shade Method” for Zones 1 and 2, the shade-dwelling species. (These are given low-level UVB across a wide area of the vivarium with a gradient to zero in deep shade, as they don’t generally bask in bright hot patches of sunlight). “Sunbeam Method” is for Zones 3 and 4, which are species that bask in sunlight. (These are given higher UVB, but limited to the basking zone in a much smaller part of the vivarium, like “a patch of sunlight” under a lamp. Vivarium should still have a gradient to zero in deep shade).
FAQS
What is a Ferguson Zone?
Using the original Solarmeter® Model 6.5 UV Index Meter, a team of herpetologists led by Professor Gary Ferguson of Texas Christian University published research in 2010, which summarized the daily UV exposure of 15 species of reptiles that were studied in the wild. These species were grouped into four zones, aka “Ferguson Zones,” according to their daily sun exposure requirements. In 2012, the British and Irish Association of Zoos and Aquariums (BIAZA) built on Ferguson’s research to produce a document allocating Ferguson Zones to 254 species of reptiles and amphibians. You can download this report here. Today, ongoing research continues to apply Ferguson Zones to even more species.
Which Meter Do I Need For My Reptile – Model 6.5R Reptile UV Index Meter or the Model 6.2R Reptile UVB Lamp Meter?
Ideally, reptile keepers will want both meters. Because the Model 6.5R Reptile UV Index Meter’s erythemally weighted action spectrum is extremely close to the action spectrum for vitamin D3 synthesis, it is the ideal tool to determine proper UV dose for your reptile, per the appropriate Ferguson Zone for the species. In fact, the 6.5R’s readings can function as a proxy for the vitamin D3-producing ability of the habitat’s light source. Meanwhile, the Model 6.2R Reptile UVB Lamp Meter is ideally suited to determine if UVB lamps are performing to manufacturer’s specifications, gauge intensity, and measure aging over time. So, in short, use the Model 6.5R to determine proper UV dose for the animal, and use the Model 6.2R to determine UVB lamp output.
References
Reptile Lighting Information by Dr. Frances M. Baines – Reptiles Magazine 2009
TOP REVIEWS

Lizzy H
Reviewed in the United States on February 4, 2026
This is a necessity for any reptile owner
So glad I bought this! I need to move almost all of my reptiles lights to the inside of their cages for them to be in the correct zones, I had no idea they were not getting enough uvb before.

david kennedy
Reviewed in the United States on January 15, 2026
it's a necessity
was extremely useful had uv light had installed not even mouth or month n half ago bought this uv meter out of curiosity tested it and turns out the uv strip light i had recently installed was barely putting out any uv and I wouldn't have guess or known if it wasn't for this product here this uv meter is an expense but it'll help you out a lot and help you to know when it's time to change out your uv when that time comes

MSWS
Reviewed in the United States on June 1, 2020
Absolutely a great investment for any reptile owner
I am so so happy I decided to invest in one of these and can’t recommend them enough for any reptile owner!!! This completely takes all the guesswork out of the amount of UVB your reptile is getting and may even save their life! Without a meter we don’t actually have any way at all to make sure they are getting the amount of UV they need. Now I know exactly how much UV light he is getting, and I can check the bulbs to measure the output so I know when they need to be replaced instead of relying on just the manufacturer suggestion. When I first got this I tested it under my current T8 UVB bulb that wasn’t more than a month old and it was barely putting out any UVB at all. Had I just followed the normal schedule for replacing them, my poor beardie who is a rescue that had MBD as a baby may have ended up suffering because of it. Needless to say I got a new light right away, but this time I got the Arcadia 12% T5 (which is considerably more powerful) to go with the larger enclosure I was also getting, and I used my new solarmeter to measure the UVI at different locations in his tank and tested out putting the light fixture in different positions in order to help me properly place it so he has a healthy gradient. I know it’s expensive, but this is one you should definitely consider! It’s a one time investment that you’ll find yourself using time and time again and coming to rely on to make sure your reptile is getting what they need. Also impressive to see that each unit is hand tested, calibrated, and comes with a certificate showing you when it was tested and certified.

Czigan
Reviewed in the United States on October 10, 2023
An absolute must!
I cannot recommend this enough. It's so nice and possibly important to be able to read your UVB levels whenever you need to. There's so many reasons this is useful/necessary. You could have gotten a dud UVB bulb and you'd never know unless you can check it. Your UVB bulb might be puttering out sooner than the recommended 6 months, and you wouldn't know it. Your UVB could be working great, but placement to basking spot may not be giving your lizard enough UVB, and you'd never know it. That can be life threatening to your reptile over long periods. If your reptile is hiding more, you need this. If they have less energy, funny stools, lower appetite, you need this!! I use it every time I clean my bearded dragon's enclosure to make sure that I have his basking spot just right for proper UVB, and started doing that when I bought the meter and realized how off it was. I had a vet visit scheduled (still went, vets are great!!) and everything because he seemed so off to me. Never basking, barely eating. I used the meter and fixed his set up (bulb working great, but the basking spot wasn't getting enough,) and I swear he lept onto his basking spot and didn't leave it for two days. Since then he's been much more like himself. This isn't a replacement for vet visits, of course, but if you aren't getting your basic care requirements right then of course your reptile won't be in top form. And since there is no other way to make sure the UVB is correct, this is the way to go. You cannot rely on replacing every six months, and you definitely cannot rely on it working because light is still being emitted. That doesn't mean anything for UVB. I know it's expensive, but just get it. In the long run it will save you so much money, sleepless nights, and heartache.

Daisy Ferret
Reviewed in the United States on July 7, 2020
Priceless peace of mind for reptile owners!
I keep bearded dragons. A couple of years back I had ordered new mercury vapor UV bulbs for my beardies but the regular brand I bought was out of stock, so I had to settle for what was supposedly a similarly reputable brand. I replaced 3 bulbs right away and within days noticed that one of my beardies was having trouble seeing and keeping his eyes closed most of the time. I worried but did not connect it to the bulb until a second beardie began having the same troubles, and then within hours, the third was also showing signs. I immediately removed all 3 bulbs as they were obviously the culprits. My two remaining beardies who did not get these bulbs had no symptoms whatsoever. All three affected beardies did recover, but the first to be blinded took the longest to get back to normal. I have since learned that this issue was almost certainly caused by dangerous UVC light which is the type used to kill bacteria and viruses, and is very harmful to living beings, and especially harmful to eyes. I've also learned that UVA and UVB bulbs created for reptiles are NOT well regulated or have much consistency even in the same brand. So having this meter to tell me exactly how much UV light is being put out by various bulbs, and at what distances from the bulbs eases my mind that I will never have my precious babies harmed by another poorly made bulb. Yeah I know this solar meter seems like a big expense, but it will save you and your beloved reptiles from what mine went through, and that is worth every penny.

Francisco
Reviewed in the United States on December 16, 2023
Works great
This seems to be working great (hard to actually gauge). I ended up moving my IV light inside the terrarium since the screen was blocking so much of the UV. The only thing I don’t like is the sensor has to be pointed up and it’s hard to get the accurate reading near the basking spot and hammock due to the device adding 3 or so inches closer to the UV source. But, I and definitely able to make sure the light is enough to keep my bearded dragons happy.

Allison
Reviewed in Canada on October 3, 2019
Awesome product!
Works great, simple to use, item is exactly as pictured! A UVB reader is extremely important if you keep reptiles and they have UVB lighting! For me personally I own 14 different types of herps and quite a few of them have UVB lighting, so investing in this tool, will ensure that I save money in the long run! The reason being is I will know exactly how much or how little UVB the lights are producing, which will inturn ensure that I am not replacing UVB lights prematurely! (As if you know anything about keeping reptiles UVB lights are not cheap!)

David N. David N.
Reviewed in Germany on September 20, 2023
Vielen Dank!!! Vielen Dank!!!
Lange habe ich überlegt, weil es für mich auch nicht wenig Geld ist. Aber ich habe es mir dann doch gekauft. Zu meinem Erschrecken musste ich feststellen, dass die Lampen bei meinen Echsen, die das UV Licht besonders benötigen, so gut wie keine Wirkung mehr haben, wer weiß wie lange schon nicht mehr. Jetzt konnte ich mal alles durchmessen und durfte/musste somit 2 neue Strahler kaufen. Dank diesem Gerät kann ich nun zeitig reagieren und entsorge keine Lampen mehr unnötig früh. 280€ sind für viele eine Menge Geld, aber im besten Fall hat man das Gerät auf ewig und wenn ich jetzt alle meine UV Lampen auf Verdacht getauscht hätte, wären es weit über 300€ geworden. Jetzt sind es "nur" 80€ für die beiden Strahler. Also hat sich das Messgerät bereits jetzt schon bezahlt gemacht.

Alan
Reviewed in the United Kingdom on November 3, 2019
High quality UV meter.
Although it seems quite expensive this is one of the only UV meters I would recommend purchasing. I carry out a large amount of zoo and exotics veterinary work and require a reliable, high quality instrument for my work. I often find clients who’s animals are not receiving the correct amount of UV supplementation despite the use of UV bulbs. A good quality UV meter is a must.

Dirk Jasper
Reviewed in Germany on August 21, 2022
Einfach super Einfach super
Endlich die UV Produktion der Lampen messen und über längere Zeit kontrollieren … zuverlässig und einfach. Top Produkt - zwar nicht billig aber es gibt auf dem Markt nichts besseres um bei unserem Chamäleon die UV Einstrahlung zu überwachen.

Pete
Reviewed in Canada on May 7, 2022
Amazing tool!
A must have for reptile enthusiasts.. getting the right amount of UV for your reptile is most important.. this meter ensures that your lights are set up properly.. you can monitor their output and know when to change them without guessing. Great product!
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