Bulb Test 1 & 2

Brand: ZooMed
Model: ReptiSun 5.0
Price: $16.49 + S & H at PetGuys
Wattage:
Type of bulb: 18" florescent tube
Special equipment: 18" florescent fixture with plastic cover removed ($7 at Walmart).
Manufacturer recommended replacement: yearly
Manufacturer recommended distance from bulb: 10 - 12 inches or less

 

Test 1 & 2 are being conducted in set ups with the florescent fixture mounted to the back of a home made terrarium. The terrarium is made of melamine wood and has a plexiglass front. The heat source for this terrarium is a 60 watt regular household bulb, which is 12 inches away from the Reptisun. The Reptisun's in both cages were brand new on August 1st, 2003. The approximate age of the bulbs when I began testing is 493 hours (14 1/2 hours a day). Since I didn't have a UVB meter at the time the bulbs were new, I will have to start testing on these bulbs that are just over a month old. I will have to wait until I can buy new bulbs before I can test a brand new Reptisun 5.0. But this test should give us a good idea of how they work and how long they last. I will continue testing these bulbs until 75 % of the UVB is gone or 12 months, which ever comes first.

This photo was taken last winter, but it's the same enclosure - instead of the Powersun bulbs we are using regular household bulbs. We will switch back to the Powersuns when winter comes. (Top cage is Lizzy's, bottom one is Mo's.) This is just to give you an idea of how I take the UVB readings. To make sure I take the reading from the same place every time, I use a measuring tape and always measure from the center of the bulb.

The following readings were calculated by taking 3 readings and getting the average of the 3. I thought this would be the most accurate way to get a good reading since the UVB intensity can change just by moving the meter a few centimeters in any direction. All readings were taken without any natural sunlight in the room. Also, to get a good idea just what these measurements mean, I took the UVB meter outside on a sunny September day (slightly cloudy and 90 degrees) in Salem, Oregon at 6:00 pm and got a reading of 59 uW/cm2 standing directly in the sun. Then on another day in September in Salem at around 2:30 in the afternoon, (no clouds and 88 degrees) the reading was 216 uW/cm2.

Also, I was asked to find out if having a regular household bulb next to a UVB bulb made a difference in the intensity of the UVB. So, I removed the basking bulb and retested both Reptisuns. There was no difference. So, to answer the question, it does not appear to make a difference in the amount of UVB produced if you have a regular household bulb or basking bulb next to a UVB bulb.

August 1, 2004 Update: I realize that these poor old UVB tubes are way passed their expiration dates. However, I wanted to keep the ReptiSun 5.0 bulbs in use so I could test them when they reached their one year anniversary. Even though we kept Lizzy and Mo's ReptiSun 5.0 bulbs going, we and added additional UVB sources to their cages (and turned them off during testing).
Bulb Test 1 (Lizzy's cage)
Distance from bulb:
3"
6"
9"
12"
15"
18"
Irradiance (measured in uW/cm2)
Week #1 (9/4/03)
49
24
14
10
7
5
Week #2 (9/12/03)
48
24
14
9
7
4
Week #3 (9/18/03)
48
23
14
9
6
5
Week #4 (9/26/03)
47
22
14
9
6
4
Week #5 (10/3/03)
47
22
13
8
6
4
Week #6 (10/11/03)
44
22
13
8
6
4
Week #7 (10/17/03)
44
22
13
8
6
4
Week #8 (10/22/03)
44
22
13
8
6
4
Month #3 (11/22/03)
42
21
13
8
6
4
Month #4 (12/30/03)
39
20
12
8
5
4
Month #5 (1/22/04)
36
19
12
8
5
4
Month #6 (2/20/04)
36
18
11
8
5
4
Month #8 (4/19/04)
36
17
10
8
5
3
Month #10 (6/21/04)
36
16
10
8
4
3
One year (8/1/04)
36
15
9
8
4
3
             
Bulb Test 2 (Mo's cage)
Distance from bulb:
3"
6"
9"
12"
15"
18"
Irradiance (measured in uW/cm2)
Week #1 (9/4/03)
59
29
18
12
8
6
Week #2 (9/12/03)
60
29
18
11
8
6
Week #3 (9/18/03)
57
28
16
10
7
6
Week #4 (9/26/03)
57
27
15
10
7
5
Week #5 (10/3/03)
56
26
16
10
7
5
Week #6 (10/11/03)
48
26
15
10
7
5
Week #7 (10/17/03)
48
26
16
11
7
6
Week #8 (10/22/03)
49
26
16
11
7
6
Month #3 (11/22/03)
48
24
15
10
7
6
Month #4 (12/30/03)
46
22
14
9
7
5
Month #5 (1/22/04)
45
22
14
9
6
4
One year (8/1/04)
40
20
12
8
6
4
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