Hi, want to share it? I am especially interested in the nutrient doser. Did you build it yourself or is it COTS?
Yes tie in one output to the optocuplers led, use a 330 ohm reisistor on the led for current control. Then you will need the jack wiring for the light, not all lights work with the PWM and some will dim. You will have to play with the frequency.
It is a custom doser I built I would sell you a board and the plans to build it but you need to have some technical know how to do it. Build circuit boards with SMD components, 3d printer, and they aren’t cheap it will cost you about $2,000.00 to build it.
I know my way around building circuit boards. I use EasyEDA and Fusion 360, and order the pcbs and enclosures at JCLPCB. But the complete doser will cost around 2k? Then why not buy one for the same money?