Water Chemistry

Chemistry Parameter	Recommended Aquarium Level	General Ocean Value
Alkalinity (KH)	150- 200 ppm, or 9-11dKH	125-150 ppm, or 7-9 dKH
Calcium	375-450 ppm	420 ppm
Magnesium	1250 -1350 ppm	1275 ppm
Salinity (Specific Gravity)	1.019- 1.021 specific gravity (25-28 ppt) for fish ONLY; 1.025sg (34 ppt) for invertebrates (or mixed aquariums)	34 ppt or 1.025 sg
pH	7.8-8.4	8.0 -8.3
Ammonia	under .1 ppm	generally under .1 ppm
Nitrates	under 15-20 ppm fish, under 1 ppm reef	generally under .1 ppm
Redox (ORP)	Balanced, see Aquarium Redox	Variable (although more important than many realize)
Silica	under 2 ppm	.06 – 2.7 ppm
Strontium	5-15 ppm	8 ppm
Iodine	Generally not a problem with modern salt mixes & maintenance, however levels should not fall below .06 ppm with most corals/algae present	.06 ppm