I have visited this pool over a period of years, whilst en route between Auckland and Wellington. It is a “must do” stop for me. A beautiful spot at 2 a.m. on a starry night. A very pleasant hot soak and a rest in hot or freezing weather. I will usually have something to eat – a pie and a coffee, when I sit down in the water. The muddy-coloured water and the scum are harmless and a natural product of the unfiltered and untreated hot springs which feed into the pool. When the water gets a bit too scummy, you can always open the sluice gate and let it flush out for a while (but do remember to close it so that the pool will fill up again). I gather that the council flush it like that once a day anyway. I wouldn’t recommend immersing your head in the pool or drinking from it, simply because there is a *very slight* risk of amoebic meningitis from amoeba that *may* live in the pool. Having said that, quite a lot of regular/local visitors to the pool do immerse their heads – including children. I have not heard of any cases of amoebic meningitis there though.