Correcting Alkalinity/Calcium issues

[Stalwart]

Hi all,

I fianlly got an ALK test kit and took my first test.

I registered about 4.3 meq/L or 12dKH
Calcium is at 375
PH 8.4

According to Randy Holmes-Farly's chart, I am above and slightly left of the target range, in zone 3. The recommended correction, was to just add calcium and move my results to zone 1 and time will correct it the rest of the way.

I dose about 12-13ml of Kent Tech CB 2 part daily.

My question is, tomorrow when I would normally add my 2 part, should I just add part A this time, and then test again tomorrow night?

TIA

 

[lcstorc]

Try using the reef chemistry calculator. It asks a variety of questions and then tells you what to add to achieve desired parmeters. It's a Boomer link so it must be good.

http://home.comcast.net/~jdieck1/chem_calc3.html

Hope that is what you are looking for.
Best of luck.

 

[Woodstock]

I would test prior to dosing to see what the tank needs. Also note that low magnesium can cause low calcium so test for that also. I recommend the Salifert mg test kit.

 

[prow]

best thing to add is CaCl. to bring it in to balance then go back to your two part additive. i second the salifert test kits.

 

[blue_eyes53813]

Lynn gave a link to a very good calculator... I had to do the same as you in zone 3... test first , if needed add a little calium(part A) test again a few hours later and keep repeating... I to bet your Magnesium is low..

 

[Stalwart]

I guess I will put a Mag test on my ILC shopping list for tomorrow. I hope they have the Sera kits I think mag is in there.

Thanks all, for the input

I will keep you posted

 

[Stalwart]

I would test prior to dosing to see what the tank needs. Also note that low magnesium can cause low calcium so test for that also. I recommend the Salifert mg test kit.

You were correct, Mag came back at 1200

 

[tatuvaaj]

Stalwart,

Your Mg is so close to natural sea water that it won't have any negative affect on calcium and alkalinity.

Your alkalinity is pretty high (4.3 meq/l) and that will make it hard to maintain proper alkalinity and calcium because of increased abiotic precipitation. I would lower the alkalinity (by letting it drop naturally) to ~3.5 meq/l or so and maintain calcium around 400 ppm. Studies have shown that elevated calcium will not accelerate calcification in corals while elevated alkalinity does.

Natural seawater has alkalinity of 2.5-2.8 meq/l and ~400 ppm Ca++.

 

[Stalwart]

Thanks Tatu, I have ceased my two part addative and started adding Kent liquid calcium to raise the calcium, just monitoring the alk and last night I was at the top of the target range at 4.0meq/L, i am looking to get it about 3.5meq/L

 

[Woodstock]

You were correct, Mag came back at 1200

Great... you'll find that keeping the mg between 1250-1350 ppm will allow for stable calcium levels. Once you boost it up a bit, you'll notice your ca will increase. When I corrected the low mg of 1170 in Tropic Marin Pro to 1300, the calcium automatically rose from 380 to around 420!

 

[tatuvaaj]

Mark,

I think that's the right way to go You can worry about the magnesium later

BTW, what's your salinity? As you probably know, both Mg and Ca are so called conservative elements meaning that their concentration in NSW (natural sea water) follow the salinity linearily. At 33 psu 1200 ppm would be a "correct" Mg concentration...

 

[Stalwart]

I just pulled out my trusty refractometer, (yes I finally got one) and it shows my SG at 1.025 or 35

 

[tatuvaaj]

Great... you'll find that keeping the mg between 1250-1350 ppm will allow for stable calcium levels. Once you boost it up a bit, you'll notice your ca will increase. When I corrected the low mg of 1170 in Tropic Marin Pro to 1300, the calcium automatically rose from 380 to around 420!

I must disagree with you on this one... Adding magnesium will have no direct effect on calcium concentration (or maybe I just misunderstood you?). Having a seriously low Mg will accelerate CaCO3 precipitation although no one seems to know how low your Mg must get before you have problems, especially in typical aquariums where elevated DOM levels will also slow down the CaCO3 precipitation.

Naturally there's no reason why one shouldn't maintain NSW levels of Mg but how much faster CaCO3 drops out of solution in a typical reef aquarium with a 10% lower Mg concentration I would really like to know

 

[Boomer]

tatu

I did not know you were posting here First time I have seen you here. Hope you stick around bud

 

[lcstorc]

Silly question here. I just tested my mag for the first time last night and I believe it was 1080. Is there a magnesium supplement that I have just not noticed? I did a water change after the test so I will test again and get numbers for ph, alk, and calc.

 

[Woodstock]

I didn't think I added calcium to that solution but I guess I did. I will make up another batch and take better notes... which reminds me that I need to do a water change before the baltimore trip this weekend :smirk:

 

[Woodstock]

Silly question here. I just tested my mag for the first time last night and I believe it was 1080. Is there a magnesium supplement that I have just not noticed? I did a water change after the test so I will test again and get numbers for ph, alk, and calc.

Epsom salts will work in a pinch but with constant usage will get the ionic balance off. I just bought Seachem's magnesium (dry) that I will use with my TM pro water changes.

 

[tatuvaaj]

tatu

I did not know you were posting here First time I have seen you here. Hope you stick around bud

I've registered here over two years ago but started posting just now. I've been "offline" for sometime...

BTW, was it Millero that studied the Mg effect on the CaCO3 precipitation? I tried to find it but my search at the Google Scholar was not succesful (I don't have access to any scientific libraries / subscriptions)...

I did find this: http://eos.wdcb.rssi.ru/transl/oce/9404/pap09.ps

 

[Woodstock]

So at a salinity of 35 ppt... do I even need to increase a mg level of 1170ppm? I have always adjusted it to 1250-1300ppm...

 

[Boomer]

tatu

No, I do not think it was Frank that did that study. He did the study on PO4 being removed by carbonate substrates, which in the real world, is actually ( a real reef) is 99 % nonsense. I'll look for you and then post it here