Don't just try and filter the well water. If you don't have a good filtration system like a RO system for city water, go down to the store and get enough bottled water. Or find a friend who has a RO system and ask them for enough water. If you don't you won't know if the water supply is an issue. You will only know if you eliminate it as a possibility. If you try and doctor up your well water, you won't know if you doctored it up enough, or if that was even an issue, or can even be done effectively to begin with. You need to eliminate it as a possibility.
If that does work, then you can try and work on doctoring up what you have. But unless you have a lab test your water supply you have no way of telling what is in it, thus you have no way to know if a filter will take out the problem, and/or what kind you need, or even how effective it might be. If you start with RO or bottled water you know the filtration system to filter it took out anything that could be a problem. Thus eliminating anything that might be in your water supply as a possible problem. And make sure to flush the growing media and water in the dutch buckets out with good water first too.
Plants can only uptake
nutrients within a pH range, if that pH is out of range it will affect the
nutrient uptake of the plant. If the plants are not getting the right nutrients, it can cause all kinds of disorders. So yes the pH issue can be causing leaf curling among many other things.
P.S. Do you have a link to the nutrients you are using?? As well as a mixing chart for them??