magnesium

I've been avoiding buying a magnesium test kit because they are so expensive. But I recently got one, and found the following: my magnesium level was 960 (calcium was 360). I recognize that both my Mg and Ca measurements are a bit low. My question is whether these levels are detrimental, and by how much should I raise them. I have a mixed reef tank with mostly softies and LPS, but one acro and one monticap, and one squamosa clam.

 

Mg should be around 1200, others have it higher, like around 1400ppm, but I believe natural sea water is around 1200. Ca should be between 400ppm and 450ppm, with natural sea water around 420ppm.

 

+1 Agreed

 

Im looking into getting a mag test kit.. which one did you purchase and how much.. I believe I've seen them before around $20-30 bucks..

 

I have the salifert magnesium test kit it works great but still is a little bit expensive like around 35

 

the namee of mine escapes me but it was 60 i think.

 

I got the Red Sea one (they didn't have the Sailfert one at my LFS). It was about $30 (Canadian) for 30 uses.

 

According to Salifert natural seawater has a concentration of 1300-1500.
I aim for 1350-1450.
Get yourself a couple of big boxes of Epsom salt from Walgreens. They're on sale there often for $2 for 2 quarts. Use this calculator:
Reef Chemistry Calculator
Don't increase more than 100 per day. It's going to take a lot to get it up to normal. It may take a whole gallon of epsom salt to get to normal in a 90 gallon.

(also I really prefer magnesium chloride from bulkreefsupply.com dissolves easier but, it cost more.)

 

This is from one of the gurus, Randy Holms-Farley;
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)

A good rule is, whatever your calc is within the acceptable range, your mag should be triple that number. Calc = 420, mag= 1260.

 

Ok guys, thanks for all the responses. Now my next question - I have a bottle of Seachem Reef Complete, which is supposed to increase both calcium and magnesium (and also strontium) proportionally. Anyone with knowledge/experience with this stuff - is it ok to use to up my levels, or do I need separate calcium and magnesium products?