Bru'n Water...Ruined Brown?

I brewed 12.5 gallons of Brown ale today. i blended my hard tap water at 50%. I set all additions in Bru'n water. Hit my ph 5.3, then when I looked at the sparge water it said I needed to use 6.3 ml of phosphoric 88% in my sparge water. Having never used any acid, I filled my syringe and added it to my 13.25 gallons of sparge water. It was the first time using my ph meter too. Works and calibrated just fine. After adding the acid I heated the sparge water the sparge water tested at 3.6 ph. I sparged and started the boil and then thought about the ph. I tested the remaining water from my HLT and found it being 3.6 and didn't know what to do. So I finished as normal and put it in the temp controlled fermenter. So the long of it.....Is my Brown Ruined? I learned a lesson on the acid, a little goes a long way.

I can't see how 6.3 ml of 88% phosphoric acid could drop the pH to 3.6 pH. I mean, it's just not possible. Not if you were using RO water.

Did you use a calibrated pH meter at room temperature?

I did calibrate and it was at 70 degrees. I thought the meter was reading accurately. It is the same meter you bought Yooper. After your problems I had it in the box for a year. I hope you are right. It was a 50/50 blend with my hard water (similar to your MI water) and distilled water. Who knows, maybe it was user error, wouldn't be the first time. Having never used acid I thought I had entered something wrong in Bru'n. I went over it several times and I guess the 6 ml was a correct dosage.

My starting sparge water ph reading was 7. The meter thing is going to take some getting used to. Not sure why I didn't tackle it before.

Is your PH meter temp compensated?

Yes, I have since found that my meter is defective.