You folks are absolutely right.
His pH was very low, 6.8 or so. I figured the Borax wouldn't do any harm.
I am afraid he is going to get frustrated and stop believing me and head for the Pool People and armloads of crap.
I saw pH minus, Alk increaser, conditioner, and so on in his shed. They sold it to him once, they'll do it again.
BUT it is his pool and I cannot be there 24/7 monitoring it, brushing it, vacuuming it and most importantly dosing chlorine and it looks like he will need A LOT from you have told me.

You know how it goes right?