So i came up with an idea to have unlimited cooling on my led cobs i have been testing, i have an aquaponics system that uses a 200gallon tank with water sitting at room temp. The fish in it are tilapia that prefer warmer temps anyways, so i have a long aluminum gpu heatsink that i mounted to the ceiling and have 4cobs with 60°lenses in parallel(for ease of install and cheap power supply). Then i ran a T off of the main line from the tank pump up to the grow bed and used that to flow through the heatsink and back into the tank. The cobs were cheap chinese cobs rated 90-110lumens per watt but im getting readings equivalent to about 158lumens per watt. It's probably also because i am running them well below their rated power. Total cost of led setup is: $40. Seriously, it is beyond cheap lol. Granted im running 5000k lights instead of 3500k-4000k and the wattage on the leds is 50w (until i get my beefier 350w 36v power supply). But this setup shows you can have decent performance for super cheap. Total cost will be up to $65 with the more powerful power supply that im getting today and i will run tests to see how they perform under that. Anyone have good conversion ratios of lux readings to equivalent par values based on color temp and type of light? That would make the testing more accurate and there is no way i can justify buying an actual par reader. Also id like to try some more expensive high wattage cobs that gain a lot of efficiency when underpowered and cooled very well. I want to reach the 200lumen per watt figure with good 4000k led cobs. Any suggestions?