Magnesium at 990 Salifert how do safely get it back up?

[Kletus429]

SG 1.026 Refractometer 1.025 hanna
Alk 7.7 Hanna
Calc 440 Salifert 490 Hanna
Ph 8.2 Hanna
Mag 990 Salifert
.05 phosphate Hanna
10 nitrates
60 gallon mixed reef

How much magnesium should I be dosing to slowly get my magnesium back to where it should be?Ive noticed a few of my corals seemed to be lightening up and and my alk dropping. I have been running kalkwasser in my ATO at around 8.5 alkalinity consistently and slowly over the last few weeks it has been dropping so I’ve set up a Kalk dripper and haven’t been able to get it on track. Decided today maybe something else is going on, ran a water sample down to my LFS and had them check everything especially magnesium because it’s the only thing I’ve never tested (I figured a 10 percent water change religiously every weekend would cover it).Well surprise surprise it’s low. Question is how can I safely get back on track?

 

[Billldg]

I took this off of the BRS site, it kinda gives you an idea of how much to raise Mag over a given time.

With the solution made and fully dissolved, measure out the amount of solution provided by the calculator and add it slowly to a high flow area of your tank or sump. For larger swings, it may be necessary to spread the dose out throughout multiple days to avoid raising the magnesium level more than 100ppm per day.

 

[Kletus429]

Ok, so according to their calculator I would need 1450 ml to get it to where it needs to be. My Main concern is a safe number to start at to gradually get to where the tank should be. I’m thinking 20 ml and check tomorrow to see where that put me. Manually dosing Red Sea magnesium chloride.

 

[CollectOyster04]

As was mentioned earlier, it is said that you can safely raise magnesium by 100ppm per day. When I had to bring mine up from being that low, I went half(50ppm per day) that, just for my comfort level. If you were to dose 20ml a day, and needed 1450ml, that would take over two months to get your mag up. Plus at dosing only 20 ml/day, you may not see a difference on a test kit over a day. I think dosing around 200ml a day would be more than safe. That would bring mag up over a week, which should be way less than the 100ppm per day threshold for you. Just a thought. Just be sure to add to a high flow area to help disperse.

 

[Kletus429]

Thank you, I figured 20 was low but didn’t know if 200 would be too much.

 

[piranhaman00]

50ppm per dose twice a day.

 

[Randy Holmes-Farley Verified Community Expert]

IMO, it is pretty unlikely magnesium is that low unless you have dosed calcium heavily for years without any magnesium. . I would confirm the reading before doing anything.

I would get your own kit and not trust a random LFS test with such a big change.

 

[Kletus429]

You were spot on. I ended up dosing 40ml of magnesium last night and calling a friend with a very successful SPS dominant tank because I just didn’t feel right about the entire situation. He assured me there’s no possible way my magnesium is that low. I picked up a Salifert kit and tested it myself when I got home this afternoon. I got 1380 twice. Lol I feel like a big dummy for believing the guy at the LFS and letting myself become so concerned.