pH Questions

[nodnarb22]

Okay, so I'm new to this and i have a possibly very complex question. The pH of my tap water is around 10.0 the ec is around 400 µs. Im using a dwc/bubbler setup. Let me first say RO water is out of the question. Purchasing distilled water is almost out of the question for sure also. Now that that is out of the way. I'm using GH 3 part micro series of nutrients when freshly mixed into water it gives me around a 6.3 pH (i have a 1 gallon just of this that is almost 2 weeks old that is rather stable at that pH). I just prepped a new reservoir last night with 18 gallons of water and the accompanying nutes for a 1-1-1 mix for general purpose my pH was around 6.5 then also today when i checked it after letting it bubble for around 24 hrs my pH was up to 7.8 or so. Ive read that that happens when you apply bubbles to a volume of water by removing the co2. I picked up a small amount of sulfuric acid and have proceeded to used this to try and drop the pH. I have used what i would equate to A LOT around 60 ml of this and it only dropped the water to around 6.6 Ive given up on adjusting it down further today to allow it to sit and see if it doesn't drop more on its own. (their are no plants in this reservoir) The other tank that i have been using for 3 weeks has a high pH of around 8 but for whatever reason all but 1 set of plants in the container appear to be doing ok (but i doubt they really are). So my questions are, will "hydro designed" pH downs benefit me at all? I'm guessing my problem is the buffering capacity of my water is insanely high. Are there any other ways to remove/reduce or combat the pH level and the resulting buffering capacity?