My FIL has a history of kidney stones (75 y/o). He swears by a supplement STONE FREE to use only ONCE stone flair.
Dose recommend: 2 in the morning and 3 in the evening. Each pill is 820 milligrams.
Any suggestions?
TIA

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9959749/

Seems like there is little to no evidence to support that kidney stone supplements do anything,

Thank you for the information. My father-in-law has recurring issues and uses Stone Free but a one case analysis is iffy.
I sent him the link.

Drink a lot of water (half gallon per day, minimum, and make sure that the water consumption is fairly steady: drinking nothing from bedtime to morning and at work and chugging a bunch of water at 8 am and 5 pm is better than nothing, but may not cut it).

Adding lemon juice to the water you drink may help.

Avoid foods rich in oxalate, like spinach, kale, collard greens, almonds, beets, etc. If you are going to indulge in those things double the water intake for the next 1-2 days.

Above advice is for calcium oxalate stones, which are by far the most common kind. Uric acid stones require different dietary recs. Hydration is the most important factor in preventing all kidney stones, except struvite stones, which are due to chronic kidney infection.