when should i start using nutrient and should i us...

USE HYDROGUARD OR UC ROOTS by cultured solutions, I can't stress this enough,,, UC roots really works in keeping your roots healthy in an always wet environment.... Healthy good water is super important to hydro.. Iv'e literally seen it "clean" root rot away.. Healthy roots make healthy plants and in my experience I'm using way less PH up and down after I found a sweet spot of 2ml of uc to 4l of water. No need to worry about reservoir water temperate as long as you have air pumps putting air into the water. Iv'e noticed zero difference between rigs that had a water cooler vs. rigs that did not.. I found using large high pressure pumps was the sweet spot for me... I use multiply drip emitters on an irrigation line. So the high pressure really helps keep the emitters flowing... Consider blacking out the tops of those nice rigs... I used a black landscaping plastic, basically a garbage bag. I found my leds actually shined light into the reservoirs through the clay pellets.. Light in the reservoir is bad. Looks like your totally setting yourself up for success. I'm just trying to share some information I found helpful. Good luck with your grow dude I'll follow along.

Pretty impressive setup and detailed journal for a first attempt. Good luck with your grow. I wouldn't put any nutes in for the first two weeks, quarter strength for the next two weeks, and half strength for two more weeks before adding the full recommended dose.

@Doobiefumes As soon as the roots are able to reach the nutrients they are good to go until then I hand water sparingly to encourage the roots to grow down towards the nutes

Hi i could write romans , but its the best you look for a good helping site. There is also a great diary for dwc newbies ( i link it in the comments. )