Without adding fuel to anything .... the following is MY 2¢ .... pesos.
I find the data sheets , spreadsheets, graphs , manufacturer dick slinging , arguements about PAR , LUX , Yield , HID , LED , FLOURO , CMH and Lights made from used placentas rather lame.
Some growers just need to put together a setup that will give them the BEST SHOT at some dank ness. Not a lot of geek jibber jabber. We ALL know that the Sun is the BAR to which we base the numbers game. It throws about 100,000 lux / and can up to 2000 u/mol doesn’t mean your plants ( or any plant ) can take that. But there are some “ power cowboys “ that “ need “ to push a 1000 w tats in say a 3x3 and aiming for 1500u/mol .... after say 1000 u/mol ... return is diminished and then you are shoehorning in CO2 .
I say be realistic.... shoot for 30 - 50 watts
PER SQUARE FOOT based on YOUR grow space , cab or tent. Target at least ... 600 + u/mol for good growth. How you hit those numbers , NO MATTER your light system choice .
You will still have to calculate the CFM of air fans / movement ... but for proper lighting those TWO variables should be the important factor for deciding. REGARDLESS of the light you settle on .... guarantee you will eventually move to other systems. HEAT was the biggest factor for me to shitcan HID ... I used cool tubes , wings and hated the stressors it made in my plants. Look at ACTUAL grows with LIGHT you are interested in .... there is where you can see what it can do .... fuck all that
“ full Spectrum “ .... “ Best of 2018 “ .... watt claims .... epistar / bridgelux , 10 watt double leds ( lol ) .
I made you a simple chart .... cuz I’m bored .... hope it helps.
Tell your “ friend “ ( * smirk ) .... double up his or her money ... it will open up better options.