Chemistry Help

[zjhoward]

I recently set up a Solana aquarium, and I've started dosing a mix-it-yourself 2 part solution from Bulk Reef Supply. I noticed that my pH and calcium were always low from my salt
(Reef Crystals), so I've been dosing magnesium (Tech M) to help get it up.
The Reef Crystals originally mixed to:
Mg: 1140 ppm
Ca: 350 ppm
pH ~ 7.8
Alk ~ 3.0 meq
I've been dosing 2-part and had my calcium up to about 400 when I started dosing the Tech M. I tried to raise my magnesium to about 1250ppm, and when I went to test the calcium, it had fallen to ~300ppm, despite the fact that I've continued to dose calcium and alk over the last few days.
Current Levels:
Mg: 1170
Ca: 380
pH~ 7.9
Alk ~ 4.0 meq
Anyone have any suggestions as to why my calcium seems so low, despite my dosing of Tech M and 2-Part? Anyone have any suggestions about how I should go about raising both my calcium and mag from here on out?

 

[nw2salt08]

Have you checked your phosphate levels?? Phosphates can suck the calcium out of the water quickly. I noticed your pH is low as well but that has a part with the Alk. Not quite sure why your levels aren't going up unless the Magnesium dosing is keeping it down.

How long has your tank been running?? Is this a new cycle?? If so, how long??

 

[zjhoward]

Yea, it may also be a CO2 issue keeping my pH down. The tank is new, and I've never been able to keep my pH high, but it seems like adding mag and 2-part actually lowered things there for a while. Who knows...

 

[nw2salt08]

What are you using to dose for calcium and alkalinity?? I ask this because the frequent use of a product caller Kalkwasser can deplete your magnesium. If you're using this to dose your tank for calcium then you might be running in a chemical circle if you know what I mean.

 

[spanko]

Why are you dosing Magnesium and the two part in a new tank?
Calcium (Ca)
Natural Seawater Value: 400 mg/L
Acceptable Range: 350 to 450 mg/L
Calcium is a critical parameter for coral growth in reef aquariums, and
chronically low levels will cause coral mortality and loss of coralline algae and other invertebrate species.
Magnesium (Mg)
Natural Seawater Value: 1280 mg/L
Acceptable Range: 1100 to 1400 mg/L
Magnesium is a very important part of the water buffering system, and is incorporated into coral skeletons. It is also critical to any photosynthetic processes.
Alkalinity (meq/L)
Natural Seawater Value: 2.5 meq/L
Acceptable Range: 2.5 to 5.0 meq/L
Maintaining an appropriate alkalinity is crucial to maintaining a
healthy aquarium. A fluctuating alkalinity will lead to serious problems in maintaining an appropriate pH, as well as problems keeping calcium and magnesium levels within required ranges.