White stuff in tank

[miaminemo]

Hey guys..have a friend who i help her with her tank.. she just emailed me and told me it looks like its snowing in her tank.. ive never seen white stuff in my tank so I dont have any idea what to tell her..

Any gut instincts?

Will

[porky]

Sounds like a snow storm caused by an Alk and CA imbalance.
If for example her alkalinity crept up too high or droped too low the calcium "can precipate out of solution" or in laymans terms the calcium is attempting to leave the tank water.
What will probably happen when the snow clears is that most of the stuff in her tank will be covered with calcium deposits (hard white spots or "dust" that doesn't want to come off). She will likely have to physically remove most of this crap!
What she needs to do is get Alk and CA back in line. Get the Alk to an acceptable range ideally 10-12 and the CA in range ideally 380-450ppm. She is going to have to test and monitor then test and monitor some more.
Long term she is going to want to look at way to keep these params in line by either dosing or running some type of automated reactor.

[szwab]

yep yep and yep

well said jason