I would reccomend liquid karma it has all kinds of microbes and humic and fulvic acids...it is one of the best things if not the best you can buy, if you just want 1 or 2 additives...and calmag+... the name tells it all...not to mention that Z uses this all the way thru...both products are by botanicare and you use them all the way with the exception of transition and end flush...and some hygrozyme or other enzyme product
to keep the res happy...just 3 of my regimen, but if I had just 3 to add to gh 3-part...
It would be these 3...honorable mention goes to voodoo juice by advanced nutrients,
but it's 60-70 bucks a liter...hope this helps