Edit: Here is a link for good information I just found. Dwc brown roots
Hydro guard and voodoo juice are just two available options for beneficials. While some plants like low 5 range for ph. It’s usually best to allow for a slight swing between 5.8 - 6.3. Some nutrients are not available at different levels, so a swing of around 1.0 is not a bad idea. 5.5-6.5
You’re ppm will depend on how many additives you will be using. I always liked to keep my Macros for the first two weeks at about 200. Less is more only because it’s easier to fix a deficiency than a toxicity. More so with hydro as pants respond almost immediately.
You’re tap water could be around 1-300 or more, depending on how close to the water plant you are. Some people prefer tap as it keeps things cleaner without much headache.
RO water is preferred mostly because of chlorine and chloramine are present in tap.
RO will require adding back cal+mag as it is stripped during the RO process.
You’re ph could be a culprit for the yellowing leaves, as nutrients become unavailable with ph level changes.
Another thing could be high ppm levels locking out other nutrients needed. Backing off will likely show improvements.
As far as plucking leaves go, I try to refrain from it. They are solar panels and should only be taken off for added value to lower canopy. However, if they are on their way out than removing them will hurt nothing. It will move the plant issues further up the plant if it has any though! I hope this helps! You’re vpd will likely not be a big issue until it comes time to flower. Powdery Mildew will take hold on plants with vpd issues, if the genetics allow for it. I think you’re range is ok for now. 