mash PH crashing not finishing

[psf]

This is my first post, minus the initial post in the welcome center. I'm fairly new to distilling. I have been distilling for about a year on a 2.5 gallon copper pot still. I would like to upgrade to a 5 gallon pot just for ease of making one run with a 5 gallon mash. my first 5 gallons mashes were used with tap water, sugar and turbo yeast. I quickly learned like I have read, that turbo had off flavors. my primary goal was making whiskey. with the turbo yeast I cut my teeth on my still and learned how to do the basics of a run. setup, no leaks, water in the condesencer, learning how to read the SG, measuring proof and ironing out any kinks.

after I few turbo yeast runs, I made 5 gal batches of UJSSM corn/sugar wash with bakers yeast. with the lack of a scale, I used two 4 pound bags of sugar, cracked corn (not sure on the weight) and 5 gallons of spring water with bakers yeast. I started having stalling problems around 3-4 generations of UJSSM due to the acidity of the backwash.

I started using a buffer of equals amounts of citric acid and baking soda to act as a buffer and I was able to take a batch to 11 generations before it stalled again. no matter what I added to the mash i.e. baking soda, sodium bicarbonate it would not raise the PH and start back up. it basically ended up as a goopy mess and I started over. the buffer moving forward help to make sure the mash would finish.

I recently quit my job and decided to retire so I decided to up my production. this was the same time every one decided to buy all the water for the COV-19 epidemic. so not alpine spring water. I decided to use tap water to make my corn mash. I made 15 gallon of mash this time using the UJSSM recipe (roughly). I also changed to DADY yeast at this time.

the all stalled with only 5% yield. Ph was under 3.0.

I though it was the water. My city water has a PH of 6.5. instead of making up 15 more gallons I decided to make 2.5 gallon at a time till I could get one to finish under 1.00.

I also made a turbo yeast with tap water during this time that did finish to under 1.00. I charcoal filter it to mix with rock sugar and peaches to make a flavored liquor.

my first 2.5 gallons was made with the following:

2.5 gallons of tap water
4 gallons for sugar
3 gallons of cracked corn
100 cc of citric acid
300 cc of baking soda
2 teaspoons of bakers yeast
starting gravity 1.074
starting PH 5.4 before pitching yeast. I always rehydrate the yeast before pitching

crashed in 3 days with a current PH of 3.0 and a gravity reading of 1.060. I use bucket heaters to keep the mash up to temp.


Two days later I started another 2.5 gallon patch with the following:
2.5 gallons of SPRING WATER
4 gallons for sugar
3 gallons of cracked corn
200 cc of citric acid
300 cc of baking soda
2 teaspoons of bakers yeast
starting gravity 1.074
starting PH 5.4

it's been several days and It's still working.....

I need some help. don't want to keeping wasting sugar and time. but I guess I need to make city tap water work. sorry for the long post but I wanted to make sure that Included everything.

turbo yeast finishes with tap water
I've changed back to bakers yeast cause I thought it was the DADY making it crash.
I've experienced success but didn't keep good records when I was so know I don't know what the problem is.

thank you for reading my novel. you can write a book on the stuff I don't know.