Its not the PH id be worrying about, it would be the hydroxide portion thats not supposed to be put in.
I dont know that much about it though, as I dont use it.
Actually that is quite a swing...
Easy,
I got my trailer tank here that takes 20 mins to fill 500 litres,
you could pick it up on the way.
You could have it in by 4 am!
check you KH and Ca levels.....