Mg

whats seems to be the biggest consumer of it ? I mean besides softies and mangroves ? My tank is stony dominated and I tested water today as a follow up to my bleachin coraline issue and my mag was at 1050.
water tested as follows.
alk 8
ca 390
mg 1050
PO4 0.03

would like to get my Ca up to 450( yes I know but My tank seems to do well there). I only have 2 mangroves in my fuge and a small amount of macro algae.
I really wana see if my thinking is correct.

 

All the corals use it in the calcification process as well as coraline. You may just not be dosing enough of it daily.

 

I recently have run into a similar problem. When I ordered all of my supplies to start dosing, I did my tests for initial values and had similar parameters.

My magnesium was only at 1000 instead of at 1350.

After reading on Bulk Reef Supply's site, I learned that if you don't typically dose, its quite normal for your magnesium to be extremely depleted.

Everything uses it, and with lower levels of mag. it doesn't matter how high your calcium and alkalinity is ... because without proper magnesium, they can't absorb it anyway ... it will just calcify on equipment.

Mg is much more important than I initially thought it was.

 

p.s - When raising up to your target value of 1350 ... do not raise your magnesium by more than 100 ppm per day, as its too big of a swing for your aquarium habitants.

a raise of 100 per 24 hours is the fastest you should try to raise your magnesium levels.

hope that helps

 

you are correct in saying the mg is the controlling agent for ca and kh. I have never ever had a mg problem until today and have begun dosing. I will prob dose daily as I have ALOT of stony corals.
I also believe this is the reason why my coraline decided to go white on me. I have only had low mg levels once since I began reefing and my toadstool was my indicator. but at that time I didnt have as big a tank nor as many stoney corals. So it looks like ima be making a decent sized BRS order so i can stay on top of things.
Thank you very much for your input, atleast now I know i was on the right track with my thinking.