And yet another Alk/Ca/Mg and Ph question

[allabarton]

I have 180g+sump 3 months old tank with a few fish, 10 SPS frags (1.5"-3"), 1 Scolymia and 1 Hammer.*
After adding SPSs my Ca/Alk started to drop. Alk stayed the same 7dKH:*
Ca 375ppm
Alk 7dKH
Mg 1300ppm
Ph 8.1-8.3
I decided to bring Alk to 8-8.5dKH and Ca to 420ppm adding Baking Soda and Kent*Liquid Calcium.*
Alk and Ca went up to desired numbers, however Ph went up as well (8.3-8.5) causing Ca precipitation in DT. Then I started dosing Kalkwasser via ATO (1tsp per 1G). Alk 8.5 and Ca 420 were staying as I wanted.*
There is only one problem: cloudy water with snow storm caused by Ca precipitation. Ph is going over 8.5. Even early morning before light time Ph stays around 8.4.*
How can I keep Alk at 8-8.5 and Ca 400-420 and Ph 8.1-8.3 and water clear?
Sorry for the long speech. Thank you.*

Alla

 

[Aquaph8]

Most likely your tank is low in CO2 which is the opposite problem most have. First off, how are you testing your PH. There are a few ways to lower your PH. First aerating your water better may help by adding CO2. Next soda water will lower your PH (please do your research on this cause I don't remember the ratios for this method). Last adding vinegar with your kalk in your ATO will also help to lower your PH ( again I don't remember the ratio of vinegar to kalk on this), vinegar is also known to cause bacterial blooms on occasion(just a precaution). Be sure your confident of your PH numbers before doing any of these and make changes slowly.

 

[allabarton]

Brett, Thank you for your reply.
I test Ph with Profilux controller probe. How can I aerate my water? My tank is not covered and staying in the room where the outside doors is left open a lot. I have ATB 1050 v1.5 rated for up to 480g.
Also I have this white dust over my sand I assume calcium precipitation. Do you think it will go away eventually? Thru my 100 filter socks and skimmer or dissolve if I raise Mg. Thank you.

 

[Aquaph8]

You could add an air stone to your sump but I would think that its effect would depend on how much CO2 is in the air. I think if you get your problem figured out things will go back to normal but Im not positive on that. Raising your Mag up to 1350-1400 will slower the calcium precipitation too. Make sure your Kalk is being added pretty slowly and the flow in your sump is mixing it well and not causing really high alk/PH in a small area. A small powerhead in the sump may be some help for this as well.

 

[Downbeach]

Same answer from me on RC:

A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH by Randy Holmes-Farley - Reefkeeping.com

 

[allabarton]

You could add an air stone to your sump but I would think that its effect would depend on how much CO2 is in the air. I think if you get your problem figured out things will go back to normal but Im not positive on that. Raising your Mag up to 1350-1400 will slower the calcium precipitation too. Make sure your Kalk is being added pretty slowly and the flow in your sump is mixing it well and not causing really high alk/PH in a small area. A small powerhead in the sump may be some help for this as well.

Thank you, Brett. I am going to test my water aeration. I'll bring Mg to 1350-1400.
Also my Ph probe is right next to the ATO with Kalkwasser dosing tube. I wonder if that could give higher Ph readings? I mix 1 teaspoon Kalkwasser per 1 g RO/DI and drip it about 1 drop per second that keeps water level stable in the sump.

I just need to figure why my Ph elevated even before dosing Kaljwasser. Going to calibrate Ph probe as well.