I notice that the Pool School's recommended pH level is 7.5-7.8.
Everything else I've ever seen (pool chemical labels, pool equipment manuals, web articles etc.) suggests it should be 7.2-7.6 with 7.4 being optimum, and have consequently spent a lot of time and money trying to keep my pH inside those parameters (it tends to drift towards the high 7s)!
Is this a climate/temperature thing (I'm in the UK) or have I just been suckered into buying more 'pH Minus' than I really need?!