Type And Amount Of Proper Lighting Needed For Optimal Plant Growth?

[Strat-Mangler]

My mother-in-law has had aquariums for a number of years but is now a little confused as to what lighting she should buy and how many of each for optimal plant growth. I am therefore looking for advice from all you experts.

Here is what she sent me via email.

"I have a 20gal planted tank (L24" x W12" x H17") and I need to know how many LEDs and the type of LEDs to light my tank for optimal plant growth. There are 3 types of LEDs which have a number assigned to them (3528, 5050, 5630(5730), 5630 (5730), the last one being the brightest. How does LUX , PAR , and LUMENS fit into all this?"

I know absolutely nothing about all of this but if you have any questions which would help in determining what she needs, please feel free to ask and I'll relay the msg. Hope you can help to solve this little mystery for her.

[Fresh2o]

Found a link (https://www.12vmonster.com/blogs/pro...-5630-5730-led) on the differences between the LEDS but PAR was never mentioned. Unfortunately, PAR readings at various depths would need to be taken to get an idea of how much light they produced (or published somewhere).
As for “optimum”, that may depend on the plants one wishes to grow.