Thats what the guy at HFF suggested too, but I've been keeping CL's for 6 years, doing 30-50% water changes straight from the hose, even in winter, and the three times I have had whitespot have all been in mid-summer when the temperature difference is at its least. Still, I'm going to try to figure a way to heat ~120L of water and get it into the tank without using buckets...
I've never heard of PP before, can you tell me a bit more about it?