on led? divide by 60 AND 55 to get an average. Blue & white ratio is also important. higher blue ratio in general will give you a higher conversion number. keep in mind light nutrient and alk levels play a role in deciding PAR ranges. This is why folks say acclimate and "watch the coral" So 20,000 is 333 apox. probably a pretty good number. and you can slowly go up from there.