Need help with high Alk

bmrigs

New member
Hello all and to Randy....

I need help with my alkalinity. I tested with Salifert and its showing off the charts at 16 dKH or 5.71 meq/L . This tank has been up and running about 3 weeks. My Ca is 420 and PH is 8.1. I am running a Geo Ca reactor set at 6.6 inside with probe. I am also running a Sulfur Denitrator that has calcium carbonate media inside with the sulfur beads. Ammonia, Nitrite, Nitrate, PO4 are all at 0. Salinity at 1.021 Temp at 77.6 One other note. My Magnesium has dropped to about 1000. How can I reduce ALK without hampering the PH or Calcium? And how can I bring back up the Magnesium to about 1350 safely? Thanks for your inputs.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
If it is truly off the charts, use a second syringe and add the values together to get a true value.

Unless you have added any buffers, then you are driving the reactor too hard (to much CO2).

I'd turn off the CO2 entirely until the alkalinity drop to about 10 dKH, then slowly restart the CO2, using a slower addition rate than before.

I would add magnesium with a commercial supplement, or MAG flake (a de=icer from Home Depot in the winter).

Don't worry about the calcium just now, but if it drops much you may want to add a bit of calcium chloride.
 

bmrigs

New member
Thanks Randy for your fast response. Yes, I would like my salinity to be higher. I will add some salt water to my ATO to slowly bring up the values. The Seachem reef salt Im using has a salinity at 1.021 when you mix it. So that is why its at where it is. Another thing, I have read on here before that you are not a big fan of Seachem Magnesium dry mix. I do have a bottle of that in my arsenal. It reads that high mag will lower alk. If I bring up my Mag to 1350, it will lower the alk some?? But in the meanwhile, I will do what you say about the Ca reactor and go from there. Thanks again for your help.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
It is fine to use what you have, but going forward, I'd use Kent or ESV over the Seachem brand. :)

It reads that high mag will lower alk. If I bring up my Mag to 1350, it will lower the alk some??

Adjusting magnesium will not impact alkalinity. :)
 

bmrigs

New member
raising Mg wont lower Alk....... shucks!!! I was trying to hit two birds with one stone.....LOL Thanks again.
 
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