Just brewed an all-grain BIAB Märzen using BF. It was my second time using the BF calculators. I found the pH recommendation to be way off. I use bottled spring water and have the water report. I calibrate my pH meter before each brew at work with fresh standards. BF recommended that I add 43 mL of 10% phosphoric acid to get my mash down to a target 5.3. Out of caution, I added half of that to the strike water and 5 minutes into the mash the pH reading was 5.11. I also use the Bru'n water spreadsheet. Bru'n's acid addition recommendation would probably have gotten me to target range without further adjustment. It suggested about 10 mL in order to achieve between a pH of 5.3 to 5.4. Any recommendations about what I might be doing wrong with my BF settings? I'm wondering if it has something to do with splitting the water between sparge and mash. I'm adding all my salts to the strike water before mash. I do a 5.8 gallon mash and a 1.5 gallon sparge. I'm still a little uncertain if I'm setting up my water calc correctly in BF. Or, should I just continue to err on the side of caution and add acid to the mash in increments to avoid undershoot?