Daily dosing of Mag?

[Chronicj7]

I have been dosing 1 tsp of kalk per 5 gallons top off water in my heavily sps stocked tank. It's keeping my calcium at around 440 and alkalinity 9.0-9.4.

I am having to dose quite a bit of magnesium every day to maintain a 1300-1350. Anyone else having to dose mg this often?

I thought it may have been my test kits but I have cross checked them with 2 other tests.

 

[greg1786]

I just recently started having the same problem. I have alk and cal 2 part hooked up to BRS dosing pumps. A few weeks ago I noticed my alk had dropped some so I upped the dosing a tad but it wouldnt stabalize. I realized my mg had dropped to 1050. 10% weekly water changes has always been sufficient to keep my mg in check but over the last three water changes ive had to dose mg every other day in between them to keep it at 1350.

 

[robert s b.]

I dose Mag with a BRS dosing pump, I go through a around 4000ml every 2 weeks. Took a while to get it dialed in, but now it's constantly around 1350.

 

[fraggin corals]

Are you using a combination of mag sulfate and mag chloride? I have been having the same issue with my mag levels and will start dosing but not sure what to use.

 

[downbeach]

I have never had to dose Mg, my WC's are enough to keep it @ 1350.

 

[kaserpick]

Are you using a combination of mag sulfate and mag chloride? I have been having the same issue with my mag levels and will start dosing but not sure what to use.

You can does either one or both. I believe Randy's two part is a mix of both. If I'm not mistaken, when you dose only Magnesium Sulfate with little water changes, you run the risk of elevating sulfate levels too high. I may be wrong about the reason, but usually it's suggested to not run just Magnesium Sulfate. Do a search for Randy's 2-part; it'll explain much better than I can.

 

[Funkateer_1]

Magnesium constantly depletes in reef tanks. Animals utilize it and skimmers pull it out.

I have a dosing pump (Vertex Libra) that feeds 5mL x 13 times a day. I use BRS Magnesium chloride/sulfate. My levels usually hover around 1350-1400ppm.

 

[fraggin corals]

My levels went from 1380 to 1120 in two weeks, even with a water change in the mix. I will have to start testing my make up water and adjust accordingly (I am using IO for my mix). I should be getting the dosing pump later this week and then the fun begins...determining how much to dose.

If I understand it should be 3 parts MgSO4 to 5 parts MgCl2. Will have to look up the thread mentioned earlier.

 

[Chronicj7]

I guess its just odd that I'm having to dose magnesium daily and my low saturated kalk solution is keeping up with the calcium and alkalinity demand. I guess I will just continue with what I'm doing.

 

[sahin]

I guess its just odd that I'm having to dose magnesium daily and my low saturated kalk solution is keeping up with the calcium and alkalinity demand. I guess I will just continue with what I'm doing.

In my experience, particularly with new tank (ie new rocks and sand) for some reason there is a lot of Mg draw for a good few months. Maybe its due to the Coralline algae growing on the rocks?

Also, when Coralline algae starts to take off growing on the glass etc, Mg draw goes up.

So what you are experiencing is not entirely unusual.

It also helps to have a salt with a higher Mg content. I use D&D H2Ocean which comes with a very decent level of Mg. However, dont spend too much on a salt just because it has a slightly higher Mg content. For me anyway, MG salts are cheap and a bucket lasts ages.

 

[kaserpick]

I should be getting the dosing pump later this week and then the fun begins...determining how much to dose.

In my experience, magnesium is a slow mover in the upward direction. That may be due to the uptake from the aquaria. That being said, when using a dosing pump, start slow, but it'll probably be more likely that you're not dosing enough (as opposed to dosing too much). I'd suggest starting slow, measuring Mg every 3 days, and ramp up to the uptake rate of your tank.

Randy's recipe suggests mixing the Mg in a small bottle, but you can dilute it in a 1 gallon jug and dose at the same rate as the Ca and Alk directions. I think that's 1ml/gal/day for SPS heavy tanks. I'd start at half that. Hope that helps!

 

[Reefvet]

In my experience, particularly with new tank (ie new rocks and sand) for some reason there is a lot of Mg draw for a good few months. Maybe its due to the Coralline algae growing on the rocks?

Coraline takes a lot of Mg, that is absolutely one of the things depleting it in your tank.

 

[Reefvet]

I guess its just odd that I'm having to dose magnesium daily and my low saturated kalk solution is keeping up with the calcium and alkalinity demand. I guess I will just continue with what I'm doing.

Why is that odd ?

Mg is consumed by the corals and coraline in your tank. If you're providing enough calcium and carbonate for them to grow then Mg is being used as well.

 

[mic209]

My levels went from 1380 to 1120 in two weeks, even with a water change in the mix. I will have to start testing my make up water and adjust accordingly (I am using IO for my mix). I should be getting the dosing pump later this week and then the fun begins...determining how much to dose.

If I understand it should be 3 parts MgSO4 to 5 parts MgCl2. Will have to look up the thread mentioned earlier.

It's probably your water changes dropping your mag. Do you test every batch of saltwater you make? I use to only test the first batch out of a bucket of salt (first bag in my case as I use the 200g box of RC), and was having trouble maintaining Mag. Couldn't figure it out for weeks. Come to find out it was my newly mixed saltwater that was dropping my mag as it was only mixing to about 1000ppm as opposed to 1450 when I tested the first batch of the box. Now I made it part of my routine to test every batch of saltwater I make before I use it.

 

[kaserpick]

That's a good point! Many salt mixes are inconsistent from batch to batch. IO certainly has been for me, which is what I would expect at $13 a bag. But, even TMPR has been pretty inconsistent. Another thing to note, if anyone uses a bucket, I've heard that the salts settle, causing inconsistency within the bucket. This can be mitigated by rolling the bucket before use, to stir everything together. Probably common knowledge to most, but I thought it worth mentioning.

 

[Chronicj7]

Why is that odd ?

Mg is consumed by the corals and coraline in your tank. If you're providing enough calcium and carbonate for them to grow then Mg is being used as well.

It's odd because my lightly saturated kalk mix is keeping up with my calcium and alkalinity but I am having to dose much more mag to keep up with the other two. Typically mag isn't consumed as rapidly as the others, specifically alkalinity.

 

[sahin]

It's odd because my lightly saturated kalk mix is keeping up with my calcium and alkalinity but I am having to dose much more mag to keep up with the other two. Typically mag isn't consumed as rapidly as the others, specifically alkalinity.

Yes, typically.

However, when I first started my tank my Mg usage was as high or more than my Alk.

My Mg uptake isnt as high as it previously was. So it does get better. Now my Alk usage is very high compared to Mg or Ca.

 

[Chronicj7]

Yes, typically.

However, when I first started my tank my Mg usage was as high or more than my Alk.

My Mg uptake isnt as high as it previously was. So it does get better. Now my Alk usage is very high compared to Mg or Ca.

My tank is a little over 4 years old.

 

[sahin]

My tank is a little over 4 years old.

EDIT: Just re-read the original post.

 

[sahin]

Also, I believe someone mentioned it earlier, but have you tested a freshly made batch of saltwater as to how much the Mg content is? It may be the salt is pretty low in Mg.

The other thing to perhaps test if not done already is to not dose for a couple of days and see how much it drops.