What in tarnation happened here my dude!? A Lux meter is ~$20.
edit: it's just the most surprising approach ever. it looks like bringing a plant into this tepee introduces more problems than the original situation, which maybe or probably wasn't even that problematic? I won't lie, I burst out laughing man. This is not meant in a bad way: why not just put the plant in the room without all that stuff? If you can grow like this, then smell or light leaks are no concern, which kind of reduces the need for a tent except for its reflective walls.
You have the right idea, you want to keep your plant haelthy, I get that. But I would rather have a plant 5 inches under that light, than inside that room.
if you ever get other lights/rooms/tents or whatever, and you want to stop the guessing game, buy that Lux meter. multiply the reading by about 0.0145 to get your PAR number. So 60000 lux is 870 par give or take 10% or whatever. It doesn't matter, it gets you in the ballpark enough.
Then you get an IR thermometer to measure the leaf temperature and presto, you never need to worry about what inch or foot or what the heck ever anymore. Feeling the warmth (if any) under the light with the back of your hand works fine too...
