how often are u dosing mag

Tommy's Reef · Mar 3, 2016

My mag drops so much within 5 days if i don't dose. I thought mag held much better? Do i have a chemical imbalance or something idk, or do i just need to dose more often due to the demand

Rybren · Mar 3, 2016

AFAIK, Mag changes very slowly and can often be maintained by WCs alone. This is certainly the case with my system.

I've seen RHF often comment that the type of drops that you are experiencing are generally testing error rather than a true drop in Mg.

ermartin · Mar 3, 2016

once i got my calcium and ALK balance to the numbers i wanted I never have had to dose MAG again. Monthly water changes have maintained it. Not sure of the correlation if any but again i test weekly and very little change

hybridazn · Mar 3, 2016

In my 10+ years in reef keeping I've never had to dose mag. Only time I did was when I had some bryopsis and dose tech m. Seems weekly waterchanges are able to keep up my mag levels.

saltyhog · Mar 3, 2016

Not sure why but I have to dose every couple of months.

Cment · Mar 3, 2016

yeah I haven't had to dose mag into my system, weekly water changes keep it steady for me. Like already stated, it seems you have an alk/ca problem or possibly a bad test kit. I would monitor both closely and see if that helps with your mg issues. How long has the tank been running? Do you currently have to dose Alk/ca and if so how do you do this.

Tommy's Reef · Mar 4, 2016

I dose cal alk and mag. tanks been up 2 years. Alk and cal every afternoon 2 teaspoons of each. Every thing is great. But my mag is getting sucked up. Quickly I feel. Just caught on to it the other day

Randy Holmes-Farley · Mar 4, 2016

tommyhere said:
My mag drops so much within 5 days if i don't dose. I thought mag held much better? Do i have a chemical imbalance or something idk, or do i just need to dose more often due to the demand

Almost certainly that is testing error. Real magnesium consumption is about 1/10th or less than the calcium consumption, so rarely more than 2 ppm per day, and sometimes less than 0.1 ppm per day.

Anything well above 2 ppm per day is testing error (assuming no big water change with a low magnesium mix).

ckozma · Mar 4, 2016

So my dosing 20ml a day of mg (split up of course) and only dosing 10ml of ca and alk is definitely wrong then if that is the case. I should actually only be dosing about 1/10th of my ca dose? So only 1ml a day to maintain mg? I do have a new test kit but only recently got it and I have been on this dosing schedule for a month!

Waters · Mar 4, 2016

A lot depends on the salt that is being used. I have to dose Mg in my new water whenever I do a water change due to my salt mix.

Tommy's Reef · Mar 4, 2016

Ok imma get another test kit and see what s going on.

Randy Holmes-Farley · Mar 4, 2016

I cannot tell from liquid volumes how much of what you are dosing to what size tank. If you gave it in ppm and dKH per day, that would be clearer.

saltyhog · Mar 4, 2016

Waters said:
A lot depends on the salt that is being used. I have to dose Mg in my new water whenever I do a water change due to my salt mix.

I think that's what changed for me. I was using a salt mix with a very high magnesium and changed to one that was just about like my target parameters except it was much lower in magnesium (actually below my target level). I've also increased my water changes which are in essence are depleting magnesium.

Randy Holmes-Farley · Mar 5, 2016

saltyhog said:
I think that's what changed for me. I was using a salt mix with a very high magnesium and changed to one that was just about like my target parameters except it was much lower in magnesium (actually below my target level). I've also increased my water changes which are in essence are depleting magnesium.

That can certainly do it. One way around the constant dosing is to just boost the salt mix. I boosted my IO salt mix for years and never dosed any magnesium to the tank.

saltyhog · Mar 5, 2016

Yep, that's the salt I switched to. Thanks for the tip! Today is water change day and I'll boost my mix to what the tank is at.

mrtian97 · Mar 5, 2016

I am using red sea salt mix, and according their website, the mg level is 1233 ppm. I do 10% WC weekly in 120 gallon tank. I use Kalk mix for ATO (4tsp in 5 gallon RODI). I supplement magnesium using Red Sea Foundation C in the amout of 2ppm of mg per day but seems my magnesium level constant between 1200-1240 ppm. Any suggestion to increase this and does my WC not helping since Red sea salt does not have high mg content?

My Ca is stable between 400-420 without supplement, same with my Alk at around 8-8.4

Thanks

briancarterkc · Mar 5, 2016

I had a similar issue and it turned out that my refractometer was out of calibration and my salinity was low. You might consider verifying your salinity with a different device than you usually use...

reefaboo · Mar 5, 2016

Randy Holmes-Farley said:
I cannot tell from liquid volumes how much of what you are dosing to what size tank. If you gave it in ppm and dKH per day, that would be clearer.

my tank is a 50 gallon with another 10 or so in the sump and im using up about 1 dkh of alk and 12 ppm of Mag per day ..

i dose alk and cal and they are super stable at 9.6dkh and 440ppm

does this seem right ?

Randy Holmes-Farley · Mar 5, 2016

reefaboo said:
my tank is a 50 gallon with another 10 or so in the sump and im using up about 1 dkh of alk and 12 ppm of Mag per day ..

i dose alk and cal and they are super stable at 9.6dkh and 440ppm

does this seem right ?

Nope. That's only possible if the water changes are the sink for magnesium. At 1 dKH of alk per day, magnesium consumption will be well below 1 ppm per day.

Randy Holmes-Farley · Mar 5, 2016

mrtian97 said:
I am using red sea salt mix, and according their website, the mg level is 1233 ppm. I do 10% WC weekly in 120 gallon tank. I use Kalk mix for ATO (4tsp in 5 gallon RODI). I supplement magnesium using Red Sea Foundation C in the amout of 2ppm of mg per day but seems my magnesium level constant between 1200-1240 ppm. Any suggestion to increase this and does my WC not helping since Red sea salt does not have high mg content?

My Ca is stable between 400-420 without supplement, same with my Alk at around 8-8.4

Thanks

If you salt mix is low, just boost the salt mix, raise the salinity, or use a different brand.