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NCC-1701
03/19/2008, 08:07 AM
I just returned from an extended trip and found the following:
CA = 500 +
Alk = 5.2
Mg = 1440 +

It would appear that my tank babysitter was not adding enough of the two part to keep up. Anyway I have been adding straight baking soda according to the reef chemistry calculator for the last couple of days to increase the alk and now have the following:

CA = 500
Alk = 8.0
Mg = 1350
pH = 8.2

How much alk additive should I continue to add each day to maintain the alk around 8.0 while I wait for the CA to come down out of orbit?

Also I have never had to add any MG supplementation and my Mg readings are always in the 1350 to 1440 range with the Salifert test kits. Would you expect this or should I suspect the test kit?

Billybeau1
03/19/2008, 09:08 AM
Depends on the brand of salt mix you use for the mag. If you list it, I can tell you if the result is likely real.

As for keeping your alk up, it'll be trial and error for a week or so.

You are at 8 today. See what you are tomorrow or in two days.

And yes, stop the calcium until it falls a little. It will. :)

NCC-1701
03/19/2008, 11:07 AM
Thanks for the reply. I am using IO salt mix.

Billybeau1
03/19/2008, 11:20 AM
If you are using IO and are not supplementing magnesium, I'd say buy a new test kit.

No way mag is 1350 in IO

For that matter, how did your calcium get so high ?

Are you sure your salinity is correct. You may get those numbers from IO if you are mixing way too rich. Say 1.030 or above.

How do you measure salinity ?

NCC-1701
03/19/2008, 12:50 PM
I mix my salt at 1.026. The calcium was from the two part that the tank sitter was adding.

I just tested my makeup water and got the following:

CA = 400
Alk = 12.2
Mg = 1440
SG = 1.026

Billybeau1
03/19/2008, 12:53 PM
How do you measure s.g. ?

NCC-1701
03/19/2008, 01:07 PM
Coral life "Deep Six" specific gravity hydrometer

Billybeau1
03/19/2008, 01:26 PM
I think thats your problem. Those are not very accurate. Your tank may be higher than you think and is why your IO is measuring high in calcium and mag. IO mixed at 1.026 runs about 350 cal and 1100 mag.

Refractometers are only about 50 bucks and a much better way to ensure your s.g. is correct.

I also think your mag kit is bad. :(

P.S. gotta go to work. Be back at 11:30 tonight. :)