A lot of people think the same....it took me roasting a tank full of SPS when I switched to LED's to teach me the lesson. Well, that and some reading.
It's true that PAR is a more accurate assessment of light (still inaccurate), but our use-case really doesn't typically demand anything more than a lux meter can do.
Consider that there are some known conversion factors of different lights...with a known conversion factor, any lux reading you take can be simply converted to PAR mathematically. You can create a conversion factor for your lights if you can borrow or rent a PAR meter from someone (friend, reef club, etc) and measure with the PAR meter
and the lux meter. The conversion factor is the ratio of lux to PAR.
The sun makes a good example.....about 100,000 lux with a lux meter, and about 2000 PAR with a PAR meter.
100,000 ÷ 2,000 = 50 The sun's conversion factor would be about 50.
Using the same logic and some practice, it's not too hard to predict a conversion factor for most lights even if there's no existing conversion factor.
But in everyday reality, most of us using lux meters don't convert to PAR....ever. The only time I do is when communicating online with someone who's only "fluent" in PAR or who's actually using a PAR meter. When I do use a conversion factor, almost 100% of the time I just use 50 because it is easy to remember and do the math in my head....remember that you're dealing with general, imprecise numbers by the nature of what you're measuring and it works fine. For example, 23,327 lux is always going to be "around 20,000-30,000 lux" when actually making use of the number. (Does that make sense?)
And
after you place the order for your lux meter, while you wait on shipping, you can download a lux meter app to play with on your smartphone. Not all apps seem to be 100% compatible with all cameras, so make sure you get good reading on a known source (like the sun) before you decide you have a good app.
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