When are you testing your urine in relation to the ascorbic dosage? I was taking up to 5 grams of ascorbic acid powder per dose at one point, and I'd check my urine during my next couple of trips to the bathroom (maybe an hour to two hours later) and was surprised that it never seemed to drop below 6 pH, in fact it was close to 7 pH at times. I don't know how quickly it's excreted though, so maybe my timing was off. When not taking anything I stay in the 6-7 range, so I'm not overly alkaline. My most acidic times are first thing in the morning and after a heavy meal.
I take my ascorbic acid an hour after each of my 3 meals. And I take my urine pH mostly at 7am, noon, 4-5pm, 8pm, and 10 pm. My urine pH goes 5.5 (or possibly below - min pH on strip is 5.5) even when I'm not taking anything. I believe it could be from my high uric acid levels (390), which although within range, is still on the high side of range. I don't know if an existing dental periodontal condition where a pocket of bacteria exists could also bring down the acidity of my ecf, but it is more likely than not.