I would never suggest adding 14 lbs. of anything at a time to the pool. Add much smaller doses of baking soda -- maybe 2 or 3 lbs. at a time. Wait a few hours, retest TA and redose until you get it where you want it. Baking soda won't significantly affect pH.
In a 25K pool, 4 lbs. of stabilizer will add 20ppm of CYA. What is your plan here? Are you aiming for a certain amount of CYA added directly and then want to use the trichlor tabs for awhile? Or do you want to just go ahead and add the whole needed amount of CYA and not use trichlor or ????? Let us know so we can better advise you. If you do decide to just add the total amount and ditch the tabs, then you will want the full 8 lbs. to get you up to about 40ppm. How did you add the CYA? To the skimmer? In an old sock hanging in front of a return jet?
How much bleach at a time are you adding? In this big of a pool, each gallon of 6% will increase the cl by 2.5ppm. Until you get a decent amount of CYA in there, you should be adding bleach 2 or 3 times a day and each time, add enough to get the cl back up to around 5ppm. It will quickly be lost to the sun without CYA and that is why you have to add more a few times per day. After your CYA level comes up, you'll be able to test and add bleach in the evenings only.
Hope this helps. Come back if you have more questions.
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