OK4450, nice work. But I’ll offer a warning. If the tank has some years on it, consider replacing it.
I’ve had acidic water creat a pinhole in a copper pipe. I patched it.
A few months later, another developed. I patched it.
A few months later, I did another.
By the time I got around to redoing the system, I had 16 squares of heater hose on my pipes with worm clamps on them, a leak under every one.
That acidic water eats through water tanks too. Your MIL may want to keep you on speed dial.
Sincere best.