Hi Alkalinity?

[smcnally]

Hi Randy,
My Alk has slowly climbed to 14.4 dKh. I'm running a calcium reactor and haven't been dosing anything else. What should I do?
My levels are as follows:

Temp: 82.3

PH: 8.14

SG: 1.025

Alk: 14.4 dKh

Ca: 350 ppm

Mg: 1170 ppm

I've started raising my Mg tonight. Wil that help the Alk?

 

[Randy Holmes-Farley]

I'd boost the calcium to 420 ppm or so with calcium chloride, and turn down the CO2 to the reactor so it add slightly less alkalinity and calcium each day, allowing the alk to drift down.

These may help:

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

Calcium Reactor setup calculator (CaCO3/CO2 reactors)
http://home.comcast.net/~jdieck1/reactor.html

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

 

[smcnally]

Thanks Randy. That article seemed to help me the most. One last question. If I use calcium chloride to boost my Ca level and get my Alk to drop do you think the Ca reactor will keep it stable once dialed in correctly? Or will I have to continually dose Calcium Chloride? I had my bubble count lower before and I had low Ca and low Alk, so that is why I was curious.

 

[Randy Holmes-Farley]

One last question. If I use calcium chloride to boost my Ca level and get my Alk to drop do you think the Ca reactor will keep it stable once dialed in correctly?

Yes, it should, aside from changes due to water changes with a low or high calcium mix (like IO or Oceanic, respectively).

Long term there will also be drift for a variety of reasons.

 

[smcnally]

Well, it seems as though I have a bad Salifert Alk test...I made some adjustments earlier today, added some Ca, waited and tested. I first got these results:

Temp: 81.7

PH: 8.20

SG: 1.025

Alk: 15 dKh

Ca: 390 ppm

Mg: 1150 ppm

It didn't make any sense to me, so I re tested my Alk with a Tropic Marin test I have and it said the Alk was at 12 dKh. I figure if I get my Ca to 420 like you said it should pop that Alk right in range, right? I should raise the Mg up another 100-200 ppm too, right?

 

[Randy Holmes-Farley]

I don't know how to tell which, if either alkalinity kit is correct, but both show it on the high side.

Alkalinity will slowly fall if you do not add any, but boosting calcium does not instantly make the alkalinity lower.

i'd target magnesium at 12540-1350 ppm, yes.

 

[smcnally]

Thanks! Maybe I'll get a third kit to be sure. I got the TM kit new, but the Salifert from someone...maybe it got contaminated.

 

[Randy Holmes-Farley]

You're welcome.

Good luck.