Disclaimer: I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.
Here's an update on my trees.I have them top fed twice a day for 15 minutes at a time. I feed them twice a week increasing nutrient solution but I follow a strict fox farm organic schedule. The Kosher seems to be doing the best and all the roots on all six plants have hit the water. I'll post some pics of the roots here soon. I do however have 2 minor problems if anyone has any advice. It would be greatly appreciated.1 I have a small amount of algae growing on the STG (suretogrow). I read a few things but I want some other opojions. 2.my water temp is around. 76 degrees and I think im about to purchase a water chiller. My little trees are two and half weeks old and are thriving. They are soakin up every minute of that solarstorm. I love the LEDs compared to HIDs the heat output is almost nothing so it always stays around 78°.
As you probably know, once the roots hit the water you really don't need to top feed...unless, of course, that's how you recirculate and then you'd want it to go more than 30 minutes a day or you're not recirculating much.
1) Water + nutrients + light = algae. Unfortunately, that STG media holds a lot of moisture and the plants need nutrients so the only thing you can do, at this point, to control it, is to block the light. I'd get some panda film (aka black & white poly), cut a circle a little bigger than your buckets, make an X slit in the middle to get it over your plants and then tape it back closed (on the underside) to block the light and reflect a little light back up. A *very* weak h2o2 solution might help kill the algae back off without harming the plants but once it starts it's not so easy to get rid of until you do a thorough cleanup post-harvest. Luckily a little algae won't hurt much, it just eats some nutrients meant for the plants. STG is better suited for ebb and flow type hydro than *DWC; I prefer Hydroton or other media that doesn't hold as much moisture.
2) 76F is too warm for me, 62-68 is best, I'd shoot for 65-ish and you'll want to consider adding mycorrhizae for root health. A chiller is a good idea but you can use frozen plastic gallon milk jugs (filled with very salty water) in your controller bucket if you have a good recirculation rate. Freeze up 2-4 of those and change them out when the water temp gets too high until you get a chiller installed.
What kind of HID setup did you have? Most people say that the SS is about the same heat output as an air-cooled HID of equal size. *shrug*
Hope that helps...
Disclaimer: I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.