I've read the same thing but I think it's readings are consistently inconsistent. So if it reads 10% (just a made up value) less than what it actually is then you can count on this everywhere you take a reading with it.
I'm also not entirely sure where this idea originated from either though. In order to verify that the par values that are read are low you would need a par meter that could actually read it correctly to make that statement.
Some industry grade par meters are more sensitive in the uv and lower wavelengths and consistently give higher readings then the hobby grade par meters we use.
Can also extrapolate from what others use vs Kessil owners. If someone using T5 needs 300 par to have sps grow but I only need 200 par then either I got super lucky and have low light versions of the same sps or the light actually puts out closer to 300 par.
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