Calcium chloride

Cory · Jan 10, 2016

i had to bump my calcium up from 350ppm to 420ppm once did that. Then i checked last week it was 300ppm! Bumped it up to 420ppm. Now its 380ppm, need to bump it up again to 420ppm. Kind of depressing lol.

My concern is i used only calcium chloride. How much chloride have i added? What can i do to add balanced calcium? Im worried the chloride is getting too high.

Taservices · Jan 10, 2016

How is your alkalinity sitting right now? In my book 380ppm cal is acceptable but 420 is a good goal as well.

I just don't want to say "do (insert thing here)" if your alkilimity is good because some options can screw with that.

Cory · Jan 10, 2016

Alk is at 8.5dkh

hanna/salifert i just raised it from 7.5dkh

Taservices · Jan 10, 2016

If that is the case, redosing with CaCl should probably be your best bet. You are probably experiencing the drop from some precipitation because of your alk (which is fine, just causes a bit more precip).

As for the Cl addition, if you added enough for the Cl to become problematic, it would by no means be your pressing concern.

JimWelsh · Jan 10, 2016

In order to keep Cl- and SO4-- in balance, you need to add SO4-- at roughly a 1:20 molar ratio, meaning one mole of SO4-- for every 20 moles of Cl-, or roughly a 1:7 ratio by weight. To answer the question, "How much chloride have I added?", I would have to know how much water volume your system has.

Cory · Jan 10, 2016

Its 28 net gallons

Randy Holmes-Farley · Jan 10, 2016

You have been adding a lot of alk supplement, right?

Cory · Jan 10, 2016

Every 5-7 days i bump it 1dkh, but now the cal is up from 300ppm to 380ppm calcification is faster.

Randy Holmes-Farley · Jan 10, 2016

Ok, I just wanted to be sure this wasn't all testing error. For calcium to drop 100 ppm, the alk would have to drop (or be supplemented) by 14 dKH.

In general this is a reason to use a two part,like my DIY or a commercial one since you need not worry about the sulfate to chloride ratio.

Are you adding anything for magnesium? That is the source of sulfate in my two part.

Cory · Jan 10, 2016

I need to add magnesium. I only have magnesium sulphate. Its tested at 1170ppm. Id like it 1250-1300ppm.

Ive boosted magnesium once that way with magnesium sulphate. 75ppm.

Randy Holmes-Farley · Jan 10, 2016

Cory said:
I need to add magnesium. I only have magnesium sulphate. Its tested at 1170ppm. Id like it 1250-1300ppm.

Ive boosted magnesium once that way with magnesium sulphate. 75ppm.

That's good. That is offsetting (probably more than offsetting)the chloride in the calcium chloride.

Cory · Jan 10, 2016

Am i looking at a potential problem? How can i fix it?

Randy Holmes-Farley · Jan 10, 2016

Probably not. I'm not even sure what the first symptoms would be of such an imbalance.

Cory · Jan 10, 2016

Id like to add 50ppm magnesium sulphate and 50ppm calcium chloride. Is that balanced? What amount would be balanced? 28 gallons.

Randy Holmes-Farley · Jan 10, 2016

Ignoring any past imbalances, that is way too much sulfate. But since you have been adding other chloride only, I'd go with it as described.

My DIY two part recipe discusses how much chloride and sulfate in that application, and it turns out to be 5:3 chloride to sulfate WHEN magnesium is dosed as directed.

Cory · Jan 10, 2016

Thanks Randy. So i could add 50ppm calcium chloride and something like 20ppm magnesium sulphate to counteract it? Sorry my math skills...

Cory · Jan 10, 2016

So I need to add 15g of calcium chloride to bring it up from 370ppm to 420ppm. And i would add 9 grams of magnesium sulphate to make it balanced. Correct?

And that 9grams of magnesium sulphate would raise my 1170ppm magnesium to approximately 1177ppm.

Instead of saying its 5:3 can we say that its 60% of the weight calcium chloride?

Randy Holmes-Farley · Jan 11, 2016

I wouldn't determine amount of magnesium additives to use based on sulfate/chloride issues.

I'd use the sulfate as a secondary issue since it is seemingly much less important.

So determine how much magnesium you need, then we can determine how much should be sulfate.

But in general, its going to be way to much bother to recalculate for every different dose.

In my DIY, you add a gallon of the calcium chloride mix, and then after that (or spread through that time), you add 610 mL of a specific mix of magnesium sulfate and chloride:

That's what I recommend you do. It is very easy.

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2006-02/rhf/index.php