Low calcium problem

[Tylerj88]

I’m losing Coral and desperately need help

these are the readings we’re getting. 
ALK: 209 ppm                Mg: 1278

PH: 8.1                             Ca: 237

PHOS: 0.0.                      Nitrate: 1

What needs to be changed?

[seabass]

Reef Parameters per: http://www.reefkeeping.com/issues/2004-05/rhf/

Table 1.� Parameters critical to control in reef aquaria.
Parameter:	Reef Aquaria Recommendation:	Typical Surface Ocean Value:1
Calcium	380-450 ppm	420 ppm
Alkalinity	2.5-4 meq/L 7-11 dKH 125-200 ppm CaCO3 equivalents	2.5 meq/L 7 dKH 125 ppm CaCO3 equivalents
Salinity	35 ppt sg = 1.026	34-36 ppt sg = 1.025-1.027
Temperature	76-83° F	Variable2
pH	7.8-8.5 OK 8.1-8.3 is better	8.0-8.3 (can be lower or higher in lagoons)
Magnesium	1250-1350 ppm	1280 ppm
Phosphate	< 0.03 ppm	0.005 ppm
Ammonia	<0.1 ppm	Variable (typically <0.1 ppm)

 

Are you dosing alkalinity (or pH buffer)?  Dosing alkalinity can push calcium out of suspension (especially when magnesium is low).  I recommend 15% water changes twice weekly to try to rebalance your water chemistry.

 

Your nutrient (phosphate and nitrate) levels are also low.  Water changes will only make this worse.  Some people would suggest more feeding, others dosing these inorganic nutrients.