Kalk and Mg in Top off ok?

[ulysses191]

HI,
I have a 125 mixed reef.
Right now i'm using an aqulifter and JBJ ATO connected to a 20g container for top off. I put in Kalk right into the 20g RO container.
I do weekly 15% water changes and my magnesium levels are always low. So i dose Magnesium twice a week. I was wondering if it was ok to add the magnesium and kalk together in the Top off water.

Thoughts?

[TampaSnooker]

Perfect - I was about to post the same question. I'm currently dosing Brightwell's Kalk +2 from my tub. It has Mg and Sr additives, which help with the low Mg a bit. It would save me a small fortune if someone had a nice formula for some Ms Wages pickling lime and their favorite bulk Mg cocktail.

[bertoni]

The high pH of the kalk solution will cause the magnesium to precipitate as Mg(OH)₂, so this approach won't work.

[jasonrp104]

Just use the calculator on the home page and figure out how much mag. you have to add to new water to keep your level the same after a water change

[Randy Holmes-Farley]

I'm currently dosing Brightwell's Kalk +2 from my tub. It has Mg and Sr additives, which help with the low Mg a bit.

Unfortunately, it is a very poorly designed product that won't work. It has very little magnesium in it, but even that will precipitate out in limewater, as Jonathan mentioned. :(

[kimber45]

The high pH of the kalk solution will cause the magnesium to precipitate as Mg(OH)₂, so this approach won't work.

so does that mean the combo products don't work?

i've been using brightwell kalk +2 for about 6 months and it seems to be maintaining my mag higher then with out it. with just w/c's i was maintaining around 1240 mag and as of right now i'm running about 1400.

here's a link.

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=19753

[jasonrp104]

What brand of mag do you dose? How much water do you change when you do?

[Randy Holmes-Farley]

so does that mean the combo products don't work?

That is what it means, yes (unless you dose the solids directly).

As far as I know, Chris Brightwell is the only one who sells such a combo.

[Randy Holmes-Farley]

with just w/c's i was maintaining around 1240 mag and as of right now i'm running about 1400.

There is no way that is from the Brightwell product.

Even if you assumed every bit of magnesium in it goes into the tank and dissolved, you'd need to add massive amounts.

Brightwell claims it contains 1,500 ppm magnesium, and I have no reason to doubt that being true.

That means that one 450 gram bottle contains 0.675 grams of magnesium. In 100 gallons of tank water, that would only raise magnesium by 1.8 ppm.

Really, this is a pitiful product. Not enough magnesium to be useful even if it worked, and it won't work.

It is a marketing gimmick, and one of the many reasons that I do not respect the Brightwell company or its products. :( :( :(

[Randy Holmes-Farley]

One other comment with respect to the magnesium.

IMO, it is risking being disingenuous to name the product kalk + 2, because normal calcium hydroxide has magnesium in it as an impurity. I expect all Brightwell's product is with respect to magnesium is the natural impurity of magnesium.

I show in the article linked below that bulk supplied calcium oxide and hydroxide have that amount of magnesium or more already in it. So to try to claim it as a plus is misleading, IMO.

Magnesium and Strontium in Limewater
http://www.advancedaquarist.com/issues/dec2003/chem.htm

[ulysses191]

Uhmm, So,
Mg dosing with the kalk in the top off, not a good idea?
As I understand it, the Mg will precipitate out of the top off water by the PH which is raised by the Kalk.

[Randy Holmes-Farley]

Yes, that is correct.

[mandingCa]

what Mg test do you all recommend?

[bertoni]

I've used the Salifert for a long time, and it's been fine. The Elos kit also gets good reviews, but I haven't used it.