Magnesium sulfate or chloride

[+Hydro]

I go through magnesium supplememnt like you wouldn't beleive. I switched to coralife salt and I'm still dosing 600-800ml of a mix of magnesium sulfate and magnesium chloride a week. I've been buying 8lbs container of each from bulk reef supply and I'm running out pretty quickly....so switching to the 5 gallon bucket. I only want to buy one because they are expensive with shipping and also I don't have a lot of room to store extra buckets. I want to just pick one or the other...what do most people use? A mix? Chloride or Sulfate? On BRS website it used to say that most people use chloride but now it says that most people use both....was wondering if that was a sales tactic so they can sell both each time.

Any ideas why I go through so much Mg? I dose it in the tank, in top off, add extra in with my fresh saltwater for water changes. I use 2 different salifert test kits so I don't think its that.

[pbnj]

Have you checked the BRS videos? They usually give good descriptions that help you decide between products. I know that's how I chose the Soda Ash for my Alk needs rather than their other Alk products (same with carbon).

[+Hydro]

I'll check it out

[subsea]

I use epson salt from the drugstore or garden supply. Without knowing your total alkalinity, I would only assume that you are precipitating magnisium and or calcium. Do you have a lot of coralie algae or hard coral growth. Both would deplete calcium and magnisium.

[+Hydro]

I have lots of small stonies, not too much coraline. My calcium drops slower than my magnesium for sure, but I do have a Ca reactor.

[subsea]

The calcium reactor could also be used to supplement magnesium. I often used aroggonite which contains magnesium as well as calcium. Also, with respect to agriculture of pasterland, in Louisiana we would add one ton per acre per year of lime (calcium corbonanate) . When purchasing this lime we usually requested a high ratio of magnesium to balance out our major nutriants. You may want to experiment with different media in your calcium reactor.

Patrick

[+Hydro]

I'll check in to that. Once I added Mg supplement inside the reactor with the arogonite and it dissolved in one day spiking my Mg to 1800 from 1150. It was supposed to be slow dissolving but its not, got it from BRS. I won't be using that again.

[stoneroller]

How low does it get if you don't dose Mg? ... and how quickly? just curious

[+Hydro]

It gets down to 1050-1150 in 4-5 days, a week tops. Usually doesn't go much lower than that.

[pbnj]

Found this interesting Magnesium info....

Corals use up bicarbonate in the surrounding sea water and turn it into carbonate and use that along with calcium to build their calcium carbonate skeletons. Magnesium binds to calcium carbonate crystals and keeps them from attracting more calcium and carbonate and growing into deposits, which can build-up on pumps and equipment.

Based on my Chemistry For Dummies training, could it be that your Ca/Alk levels are too high, thereby using up a lot of Mg in the binding process? It would be an interesting experiment to see if by lowering your Ca/Alk levels, you also lower your consumption of Mg.

[+Hydro]

Found this interesting Magnesium info....

Corals use up bicarbonate in the surrounding sea water and turn it into carbonate and use that along with calcium to build their calcium carbonate skeletons. Magnesium binds to calcium carbonate crystals and keeps them from attracting more calcium and carbonate and growing into deposits, which can build-up on pumps and equipment.

Based on my Chemistry For Dummies training, could it be that your Ca/Alk levels are too high, thereby using up a lot of Mg in the binding process? It would be an interesting experiment to see if by lowering your Ca/Alk levels, you also lower your consumption of Mg.

hmmmm, interesting. I try to keep my Ca around 450 and my KH around 10. I'm not sure I want to readjust my dosing and Ca reactor to find out though, sounds like a PITA. I'm out of Mg supplement at the moment and haven't dosed in about a week or so. I checked my Mg levels yesterday and they were 1150 ppm. To bring my tank back up to the desired 1500 ppm it will take 10 lbs of the supplement. So basically it will take 1 1/4 of the medium sized jugs that BRS sells to bring it up to proper Mg levels...at a cost of about $25 with shipping. That sucks, I'm probably spending $50 a month on Mg supplement alone.

[subsea]

$50 a month is a lot for magnesium use. I suspect either totalal alkalinity or magnesium hardness is too high. Because your calcium reactor is addding a lot of TDS and you are adding Magnesium, someting is reaching saturation and falling out of solution. I have seen sand beds cement up with heavy calcium/magnesium scale. Good luck, you need a better chemist than I.

[+Hydro]

Thanks for the suggestion. It may very well be something like that b/c I think that it excessive too. That is one reason that I wanted to post about this, to find out what others are having to dose. I know that lots of people done't even test for Mg but if you do how much do you add per week and what is your system size?

[offroadodge]

try and just keep KH around 8-9, mine stays there. It shld help. Trying to keep it high like 10-12 is tough in a big tank. JMO

[+Hydro]

try and just keep KH around 8-9, mine stays there. It shld help. Trying to keep it high like 10-12 is tough in a big tank. JMO

Makes sense, maybe I'll dial back my KH some. Don told me about a Mg supplement that I can mix in with my reactor media called zeomag that he uses and it keeps his levels around 1400, I'm going to order some and give it a try. He uses 10 to 1.

[subsea]

Thanks for the suggestion. It may very well be something like that b/c I think that it excessive too. That is one reason that I wanted to post about this, to find out what others are having to dose. I know that lots of people done't even test for Mg but if you do how much do you add per week and what is your system size?

You sound like an engineer. I used to be an engineer. Now I am a philosoper. As I quote Bod Dylon, "I am watching the river flow", every now an again I jump into the river. Bonzai.

Patrick

[+Hydro]

Not an engineer, barely gruadated high school actually . I tell people that I'm not that smart, I just think alot. If you think about anything long enough you can come up with an answer.

[pbnj]

I recently read that some corals (and especially coralline algae) consume more magnesium than others and that adding some dolomite to your reactor media will raise/maintain magnesium.

[barderer]

Hydro,

You will get a good answer to this by posting on the chemistry section of Reef Central. Lots of good chemists there.

N

[pbnj]

Actually, the response I posted was from the RC Chemistry section.

[+Hydro]

I've been out of town for a while until yesterday, I'm still trying to catch up on tank stuff. I never posted anything on that forum. I'm going to look in the dolomite, thanks for the info.

[subsea]

Not an engineer, barely gruadated high school actually . I tell people that I'm not that smart, I just think alot. If you think about anything long enough you can come up with an answer.

Bravo. With the rightattitude, anything is possible.

Patrick