Magnesium Chloride dosage

[bolza171]

Folks,

I have a relatively new setup and I'm struggling to raise some of important components, I'm looking for some advice.

I have a 270g system running for 4 months. I installed the Calcreactor last week but I'm still struggling to fine tunning its bubles.

Calcium is at 370 and I can't get it raised.
Alk is at 11.5dKH

Mag is at 1125ppm and I'm adding once a month Magnesium from Tropic Marin but as I live in Brazil, it's VERY expensive and has demonstrated to be not that effective.

I was considering to buy Magnesium Chloride at drugstore but I don't how much should I dose to raise about 150ppm.

Can anyone suggest me what is the dosage per galon to raise certain amount?

Any suggestion to raise the calcium or just wait the Calcreactor to make it happen? It's out put is at 30dKH.

BTW, what should I use? Magnesium Chloride or Epson Salt

Thanks in advance

Bolza

[Ninong]

Using magnesium chloride is better than using epsom salts but it's alright to use epsom salts as long as you don't get carried away with it and use it all the time. I have used both. The problem with epsom salts is that it takes a lot of it to have any effect and if you use it all the time, you run the risk of raising your sulfate levels. I have a 120-gal tank and I usually add only 1 Tbsp of magnesium chloride per day or 1/4 cup of epsom salts per day. When using epsom salts, it is important to dissolve it completely in a couple of liters of tankwater before adding it back to the tank. Granted, it takes a long time to raise magnesium levels at those dosage rates but I would rather be safe than sorry.

However, if your magnesium is at 1125 ppm already, I wouldn't be too worried about it. If you want to try to raise it, go ahead. I don't think you have anything to worry about as long as it remains above 1000 ppm. Ideally, you want it around 1300 ppm but 1125 ppm is really not bad at all.

Your alk at 11.5 dKH is fine! Your calcium at 370 ppm is just a little bit on the low side. You could raise this by adding just the calcium component of one of the two-component calcium-alkalinity supplements, such as C-Balance or B-Ionic. Once you get it up around 425-450 ppm, then you could discontinue the calcium additives.

Or, you could just sit back and relax and wait for your calcium reactor to do the job because you really don't have a problem right now.

P.S. -- The magnesium chloride that I use is actually a liquid. It's E.S.V.'s B-Ionic Magnesium. I could add more than 1 Tbps per day but I prefer not to.

[bolza171]

Ninong,

Thank you very much. I'll add some Magnesium and wait few more days to see Calcium response. Based on your tank and experience, I'll use 2 Tbsp per day until I reach about 1275/1300.

I'm concerned with calcum too because I haven't noticed any Coral algae in the tank so far. My previous tank had these algaes very soon.

I just moved about 6 inches closer the MH bulbs to water level aiming to increase their intensity. ( this just created a conflict with Wife).

Regards

[Ninong]

I'm concerned with calcum too because I haven't noticed any Coral algae in the tank so far. My previous tank had these algaes very soon.

I wouldn't worry about coralline algae. As long as you maintain your calcium and alkalinity levels above NSW values (7 dKH alk & 410 ppm calcium), you will have coralline algae whether you want it or not. My experience was that once it got started, it took off like crazy and covered everything within a few months. I usually keep my alk between 10-12 dKH and my calcium between 425-475 ppm and I have coralline all over the place.

If your tank has been up and running for four months, you will probably start to see coralline algae very soon.

[bongobrian]

Hello Bolza,

I don't have much experience with calcium reactors so I can't really help you there. As far as your magnesium goes, are you doing regular water changes with a high quality salt mix? High grade mixes such as Reef Crystals or Seachem Reef Salt contain many trace elements including magnesium. I've found that doing water changes has helped to raise and maintain magnesium levels.

You're actually doing pretty good with Ca at 370. You could always dose a Calcium supplement. I like to use (in powder form) reef advantage calcium by Seachem.

If you want to grow coralline, Ninong is right that it will grow as long as alk/ca is in check. Also keep in mind there are certain things that will promote and also inhibit the growth of coralline. High levels of phosphate can inhibit the growth of coralline because it interferes with calcification. Use RO/DI water and don't overfeed or overstock the tank. Coralline also grows best in areas of lower light, and prefers the blue end of the spectrum. I'm not saying it won't grow in areas of intense light, but it prefers areas of lower intensity blue light. Try running just your actinics for a period of time each day. I run mine in the morning before my halide comes on, and in the evening when the halide turns off. I really enjoy watching the tank at these times. Having a lot of current in your tank will aslo help promote coralline growth. HTH. Good Luck!

[ericb]

To know how much to add you need to know the concentration of the product you are using. If using MgCl salt dry, its relatively easy. Convert ppm to moles - there are online converters to do this.

If using a manufacturer's product, you will have to figure it out. Take a liter of distilled water, add a known amount of the product and measure the Mg content. Then use the formuala C1V1 = C2V2 (concentration of first solution)(volume first solution) = (concentration of second solution)(volume of the second solution)

You'll know the concentration by adding a known volume of product to the liter of water. You'll know the size of your tank and the concentration you want, so fill in for V1 and you'll see how much of the product you'll need to bring up the tank.

[bolza171]

Brian and Eric,

Thank you for the inputs.

I believe that Brian's comments brought me where I can have the problem. The Phosphate level is still above the ideal. ( currently 0.1-0.2).

I've been controling as much as I can the entrance of new phosphate but it's still at the high level. I'm also adding about 1g/day of Kalwasser solution.
I don't overfeed and I have small amount of livestock so far. 4 small ocellaris, 2 small tangs ( yellow and Kole) and 3 small SPS.

I've performed 20% water change per month and additional changes when I need to fill/refill the QT- 10gallons ( 2.5%) twice a week. I've used Tropic Marin salt and Red sea Salt. It's difficult to find a wide variety of brands here. I use RO/DI water only but I know the water coming out still have a some level of PO4 ( about 0.1). The tap water where I live has enormous amount of phosphage 1.0.

Besides the RO/DI water, I'm also using PO4 Remover from Coralife which is the only one I can find at LFS in Brazil.

My actinics bulbs run 3hrs longer then MH ( from 11:00am to 9:00pm and all the MH bulbs are 14K.

Many thanks.

Bolza

[rayjay]

Randy Holmes-Farley does not recommend magnesium chloride as a standard way to boost magnesium levels.
Magnesium chloride is best used in conjunction with the two part formula he came up with.
He recommends Bingmans formula as a stand alone supplement. 10 Parts epsom salts to one part magnesium chloride

SEE THIS THREAD ON RANDY'S FORUM

[ericb]

Wow - my best friend in high school was from London, Ontario. He was the only other kid who was a certified diver like me at 12.

Anyway, why would calcium chloride boost magnesium? Also, epsom salts probably should not be used in cases where magnesium levels are very low as that much sulfate is probably not good for the tank even though there is a lot of sulfate in seawater; whereas mag chloride - if relatively pure - would not likely skew any anions since you are essentially adding Mg and Cl and seawater can practically take as much Cl as you have to add of any salt.

[rayjay]

That was a big screw up on my part, and should have read magnesium chloride. I had just made up a new batch of home made salt water and the last chem I put in the container was calcium chloride. I do use magnesium chloride and not magnesium sulphate in my formula as it uses sodium sulphate for the sulphate ions.
I'm not much on chems, but I respect the advice of RHF on the matter and I believe it has to do with ionic balance, same as Craig Bingman had mentioned years ago in one of his articles.
I'm looking forward to next month to see an updated article on the matter.
"Craig's article is a fine recipe for a stand alone DIY magnesium additive. In the July Reefkeeping magazine I'll show a similar recipe for such a stand alone product, and will show exactly how ionically balanced or not different recipes are over time." (excerpt from one of RHF's posts on the link I gave earlier)

By the way, London is a GREAT place to be, but it has no reefs nearby so it sure sucks in that way.