Apple Cider Vinegar- supplement Gastric issues

Hi all,
I was wondering if anyone used ACV in small amount to aid their pooch gastric problems? Symptoms include: lip smacking as if he’s got dry mouth with no vomiting whatsoever and no rumbling tummy noises either (these symptoms can be intermittent). The high acid was also confirmed with a vet (numerous tests done, scan etc.) however, he couldn’t pin point the root cause of it. Changed diets to see if any improvements noted and it seem to be doing okish on a grain free white fish kibble (also adding plenty of liquid to food, feeding in stages and not in 1 go, pro/pre probiotics, slippery elm powder, healing clay etc.). Im also unsure if the seasonal changes affect this type of behaviour.
Have done a bit of research online however, no scientific data found on usage of ACV as such.
Any advice will be greatly appreciated.
Angela & Major (beagle)

Re lip smacking mine did that and we found out later he had tooth ache and had a tooth removed months later the poor thing as we couldnt find any thing wrong at the time.
Is the dog suffering from reflux as you vet has said hes got a lot of acid ? Is there an anti acid tab that vet could trial to see if it helps along with a scale and dental check thats what i would try.

Ummm teeth and gums all checked and couldn’t find anything wrong.
This is being going on intermittently for over 1 year and for the love of god I don’t know what else I can do about it.
The results showed he was over the threshold … he recommended Opremazon however not recommend for long term use and again he couldn’t pint point the reason why is happening…

Is it worth trying for 12 weeks to see if there is an improvement then like humans do a short course can sometimes do the trick then you could look at his diet with fish diet or diet reducing the acid rather than red meat ect just a thought