Im trying to dial in my UVB levels under Arcadia 12% t5 HO. My substrate is oyster shell and is only 1 inch deep(Testudo Kleinmanni). Since the solarmeter 6.5r is 4 inches tall, I cant sink it down far enough into the substrate to give me a reading at the substrate level. I tried to take a measurement outside of the enclosed vivarium by pulling out the fixture and measuring the same distance. However, the inside of the enclosure is all white. Especially compared to my wood floors. Does this effect the UVI recorded level. How do you most accurately measure UVI with this meter if you cant sink it 4 inches down into the substrate?