Dosing Mag & Calcium

[Missy]

Hi guys, can anyone tell me the best way to add magnesium, calcium and KH to my tank? I pour into sump near return pump but I'm not sure how close together I can dose these or if one should go in first etc.

Also I have recently been increasing the magnesium and am finding it harder to keep my calcium level up, does that sound right?

[Amphibious]

There are several theories on this, mostly it doesn’t matter. I take a pitcher of ro/di water add my three elements together and dump it into the sump near the intake.

Are you testing Mag? It is true, if your Mag is allowed to drop it will be harder for you to maintain Calcium levels. When Mag drops to around 850ppm it will be impossible to maintain Cal above about 350ppm. You can dose Cal till the cows come home, test it at 450 and an hour or two later it will test 350. It precipitates out.

Dosing Mag regularly to 1200ppm or higher will allow you to maintain 450 Cal or higher. NSW has Mag at 1250ppm and Cal at 450ppm. Don’t forget to dose Alk right along with Cal in equal parts.

Dick

[Missy]

Thanks Dick, yes I am testing mag, it was low around 1100, kh was 7 and calcium was 420. I started adding Kent mag additive, B-Ionic kalk and calcium and yesterday it read mag 1200, kh 9 but calcium was 400. I don't understand why my calcium dropped, I will test again today to make sure I didn't do something wrong.

[Missy]

Yesterday I dosed 100ml Calcium and 180ml magnesium , I didn't add the kalk because kh was testing 9. Today Calcium has dropped to 380 and mag dropped to 1170, kh is still 9. Why would this be happening?

[CarmieJo]

Did you mean that you didn't dose alk? Kalk is used to maintain Ca and alk when they are at correct levels.

To me it sounds like something it taking up Ca and Mg.

Here is a good explanation A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH by Randy Holmes-Farley - Reefkeeping.com (http://reefkeeping.com/issues/2006-06/rhf/index.php). Ca and Mg are proportional to each other and Ca and alk are inversely proportional.

[PapaMcEuin]

What is a good Magnesium test kit? Another question is regarding Strontium. When do I need that and what is the test for it?

[CarmieJo]

I have this one Seachem. Reef Status: Magnesium (http://www.seachem.com/Products/product_pages/RS_Magnesium.html).

Strontium is used by corals, gastropods and cephalopods. There are test kits available. I personally don't dose Strontium.

[Missy]

Did you mean that you didn't dose alk? Kalk is used to maintain Ca and alk when they are at correct levels.

To me it sounds like something it taking up Ca and Mg.

Here is a good explanation A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH by Randy Holmes-Farley - Reefkeeping.com (http://reefkeeping.com/issues/2006-06/rhf/index.php). Ca and Mg are proportional to each other and Ca and alk are inversely proportional.

Yes thats what I meant, should I add the alk anyway even if it is already at 9?

[Missy]

Thanks again for the link Carmie. You sent this before and I couldn't find it.

[CarmieJo]

I know the directions say add the Ca and alk in equal measure but I would add in accordance with my tests. At an alk of 9 you are right in the middle of the range so it would not hurt to dose alk to maintain it. (I keep mine between 9 and 10.) On the other hand if it was 11 you would not want to because it would drive your Ca down.

[Missy]

Thanks for the great info again Carmie. I was originally told be my lfs to maintain kh at 7 but I now believe that is risky in case it drops abit. I tested today and calcium was back up to 400-420, mag above 1200 but kh had dropped to 8 so I have added 180ml of mag, 100ml of calcium & 100ml of kh. Still looking into calcium reactor.