Help: mixing water

[kien]

I thought reef crystals had high(ish) levels of calcium and magnesium? Isn't that why it is more expensive than Regular IO?

Anyway, these days I dont dose my new salt water (I dose my main tank) but after mixing my heater and the inside if the mixing drum is coated with a fine white/brown powdery substance. I read that this is normal with regular IO. Not sure if it is the same as your powdery substance tho. It has been like that for me for a long long time. Doesn't seem to affect anything and I just accept it :-)