will mag precipitate?

[roons]

hi randy, this morning at 5 am my tank was super cloudy, never had this b4.......................my ph dips way down for some reason at night when i close up house after being normal during day.............its usually low all winter from co2 but i never see it get this low......................its 8.2-8.3 day , this morn it was 7.70.................i ran some tests, i thought maybe i was having a calcium precip event......................calc was 455 and alk was 3.00 meq/l..............................but my mag was 1170, and i had just added a bunch on sat..........................this seem odd?

[Randy Holmes-Farley]

Magnesium is slowly accumulated in calcium carbonate as it precipitates, but magnesium won't precipitate on its own.

How much did you add? What was the level before you added it? It takes a large amount of magnesium supplement to boost magnesium significantly.

This calculator shows how much:

Reef Chemicals Calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

[roons]

so mag would also lower if it was a calcium precip event? shouldnt my calc level been lower tho? and how long do these events last? is it possible for it to be cloudy at 5am and perfectly fine at 9am when ph goes back up?

[Randy Holmes-Farley]

so mag would also lower if it was a calcium precip event?

No, not enough to notice in a single event. By precipitation, I mean the ongoing use by corals and coralline algae, and also in any abiotic precipitation that is slowly happening.

[roons]

i do appreciate the help randy, but could you answer my other questions? along with, does this calcium precip event hurt the inhabitants in any way? is it nothing to worry about?

[Randy Holmes-Farley]

Calcium precipitation events where the whole tank looks like milk have not, IME, hurt animals. If the pH is too high due to the event being caused by hugely excessive limewater, then animals can be hurt. All such events take a day or more to clear the water. Transient cloudiness is not likely calcium carbonate precipitation. This article has more:

What is that Precipitate in My Reef Aquarium?
http://reefkeeping.com/issues/2005-07/rhf/index.htm

Calcium at 455 ppm is just fine. Even at 550 ppm it will not cause a big precipitation event. I'd raise the magnesium to 1250 to 1350 ppm.

[roons]

ok, thanx

[Randy Holmes-Farley]

:thumbsup:

Happy Reefing. :)