The water is completely stripped of everything when it comes out of the RO unit... The only things that are kinda valuable in tap water to plants is the calcium and magnesium which is why its suggested to put it back, most people that are able to use aerated tap water (its usually decent if its around 100ppm) dont have to worry about ca/mg def.'s because the water has it in it already, some plants require more obviously but for the most part if you amend your soil with lime or whatever ca amendment, you wont really have to worry about it with tap... But we arent using it so we have to worry about.. Thats why I suggest starting with the ca/mg+ (general organics only here... seriously, all the others have 4 letter acronyms like EDTA and others that I cant think of right now that are better left at the hydro store for non-organic grows), you add that first so you have your "base water" all set which should eliminate ca/mg defs at any point as long as you start with that all the time except for the final weeks before harvest (straight RO only at that point)....
Quickly, take that superthrive and punt that shit into the nearest trash can... And calm down with the azomite... 4tsp is way to much... An 1/8th of a tsp (yeah I said 8th of a tsp) is good for up to 10 gallons of tea and only use that 1/8th of a tsp every 3rd-4th tea, azomite is potent shit and will quickly and easily cause salt built up killing off the micro-herd just like a synthetic nutrient will but much faster... I'm not sure what sea green is but you wanna keep the liquid based nutes to a minimum, the maxi-crop products are good and most bottled fish ferts are good also, but for the most part try to steer clear of them other than the mentioned stuff but always try to keep your NPK ratings below 5 for teas except on the guanos I'd say... If you are gonna use a bottled product, try to research it and see whats in it before using it... Also if it doesnt have an OMRI sticker, its probably best left on the shelf especially if its made by one of the MMJ specific grow companies. As I said about the 4 letter acronyms... if you see those on a bottle that says natural or organic without an OMRI label, leave it there...
As far as whats in city water being "buffers"... basically, kinda... Its just the shit thats in water like iron, calcium, magnesium. you get the point, most times you can go to a local city's website and they'll show you the break down of whats in your water.. but the effect of that stuff in your water acts like a buffer making the PH more "sturdy"?? It will take more PH up or down to get it to move and doesnt sway easily with anything you add to it... RO waters PH will swing wildly if you put a couple drops of anything in it because it has no dissolved solids in it to keep it stable... but thats not a bad thing... so whatever you add to it will, yes... drop or raise the PH hard... but because your soil has lime, oyster shell etc.... the water/solution/teas are going to adapt to your soils PH much easier and not impact the micro-life as hard, however... in either case, over the past year I've found it to be pointless to PH any of it... The more I worried about it aside from knowing what the values are, the more I caused problems by adjusting it...
Also, do not trust run-off as a guide to your soils PH... I would say maybe if you used RO water with nothing added but I cant really say that method is anywhere near accurate... Spend a few bucks on a soil PH meter... It doesnt even have to be a top $ one, but stay away from those 3 pronged things... A single probe style is what you want... I'd say you can find one for less than $40 that as long as you keep it clean will last forever... With that you can check soil that is cooking, soil that your plants are in etc...
If you feel you must adjust your PH, use citric acid or something organic and only change it slightly, I honestly suggest just leaving it alone. Taking a tea thats literally beaming with life that has whatever PH value, and then adjusting it, is just killing off life... and once the tea hits the soil is going to change to what the soil PH is anyhow... Its kinda redundant no? I havent adjusted the PH of anything in over a year and I'm doing fairly well, actually I'm finally getting better exponentially because I'm learning to keep it simple (KISS)... My time is better spent getting to know my strains and figuring out worm farms and recycling soil etc... When you see people watering their lawns, are they adjusting the PH of the water? No... they put down lime.... most people dont even know what PH is or why they need to put down lime in the first place.... They hear about PH on deodorant commercials for the most part....
And especially seeing your teas are literally perfect at 7.0 without adjustment... dont even bother dude.. You couldnt ask for a better PH if you tried, but again its not necessary because you are not feeding the plants, you are feeding the soil... people say it and read it constantly but they still feel the need to do this extra work thats more harm than good... I see people ruining their grows with this shit here in this forum and all the while people coaxing them into it and getting indignant if you say otherwise when they havent a clue, they think they do..... I know because I was one of them myself... "the way I know is best because its what I know"... I said this to another forum member recently... Its cognitive dissidence... people loose their minds because you say what they are doing or know is wrong, because someone they believed to be right told them it was or they read it on a forum... These forums are loaded with complete and utter bullshit... Theres literally decades of good reading knowledge here and on other forums, but you have to sift through a metric ton of bullshit to get a gram of gold...
Keep it simple is the best route brov... If you are using supersoil... You really dont need all that other stuff. Its not a bad idea to once in a while give your gals a tea to get the life beaming again but for the most part the supersoil will take care of everything... I honestly suggest not doing any of the extra shit like teas and all that with a round of supersoil hitting them with a sugar product at days 30 and 45 of flower as sub recommends to see what it will do for you without the extras... Then try a few teas here and there and see if its getting better or worse.... More is not better... Its a tough mentality to break out of, I'm still fighting myself daily on these things but you will see a difference once you find zen in the grow room... And by no means have I found it, I'm just on the right path finally... I think.....
The one time I'm finding its beneficial to hit my girls up with a heavy N tea is during the first weeks of 12/12 where the N is gonna get used up hard. If you are seeing deficiencies or any kind of leaf abnormalities in veg, dont flip them until you get them nice and healthy... Your leaves should be that nice dark green pre flip with no crunchies of any sort...
Good luck, if you need more help feel free to ask... and again.. keep it simple...