Please Help, Mag Levels

[Mzj7725]

I posted this a little while ago in the wrong thread i think!

My corals are beginning to struggle. I am fairly new to corals (3 months in) and only 15 months into reefing. I have hammerhead, 2 frogspawn, trumpet coral, duncan, birds nest, GSP. Hammerhead and frogspawn are doing the worst

75 Gallon with 30 gallon fuge

Mag - 990
DKh - 8.9
Calcium - 380
Nitrite nitrate ammonia - 0
PH - 8.2
1.024 salinity
Temp - 78.2

I use instant ocean reef crystals and do 7.5% water changes weekly

I know Mag is supposed to be up to 1300. First question is why is it low and second question is how do i get it back where it needs to be.

THanks

[Brieninsac]

Have you been dosing for low alkalinity? I have and I'm seeing my Mag dropping. Although I was only at 1,200 ppm as of yesterday. I'm going to do a 30% water change tomorrow, which should help correct it. If not I got some Seachem Magnesium to dose if necessary.

[Mzj7725]

I have never dosed before. Should I purchase Seachem Mag and start dosing that?

[Bogue Chitto]

I added some to my tank and got it pretty stable.

[FullBoreReefer]

I buy Kent Marine Tech M in 1gal jugs. It's cheaper that way, and then you won't run out. Cheapeast I've found is $32/shipped for a gallon.

I needed excess to drive up mag levels to help fight algae issues.

[oseymour]

What test kits are you using? If
You are using the Red Sea kits. I've seen people make a lot of errors reading the kits. It's hard to get that low mag if you are using reef crystals and changing 7.5% a week.

[bertoni]

I agree that the test kit might be having problems. 990 ppm is rather low. Had you checked some freshly-mixed saltwater? If you got a bad batch of salt, that might explain a lot. I'd get a second on the SG measurement, as well as the magnesium.

[downbeach]

I would make it a habit to thoroughly mix your salt mix whenever you start a new container to eliminate the possiblilty of elemental stratification that may have occurred during shipping. Secondly, I would make sure your adding enough salt mix when you make up your WC water, i.e. if you're using a swing arm type hydrometer to measure with, you may, unknowingly, not be adding enough salt mix, and by extension not enough of those other elements(Ca, alk, mg, et al). I would get your SG up to 1.026, measured with a properly calibrated device, i.e. refractometer calibrated with a 35ppt solution, etc. Check your make up water, Mg in IO should be reading ~ 1350ppm @ 1.026(35ppt). What test kit(s) are you using for Ca, Mg and alk?

[Mzj7725]

I am using Sailfert For ALK and Mag and I am using API for calcium.

I do have a refractometer. The sailfert test kit I just got in the mail yesterday. The directions seemed a little complicated but i went through the process three times and got the same results every time. Ill youtube directions on how to do it and make sure i am doing it right.

I ordered Mag on amazon (2 day shipping), will that be something that i add directly to the DT?

[hkgar]

If you have a sump, dose to the sump. I would also dose Calcium as I like to keep it at about 440.

[Mzj7725]

I just tested it again using a youtube video and i was doing the test the proper way. My Mag levels are between 990 and 1020.

Also What Brand calcium should i use? Like i said at the top I have never dosed anything before. Is Calcium something i would add to the sump as well?

THanks

[hkgar]

Yes, all dosing should be into the sump.

Here is a link to determine how much to dose:
http://reef.diesyst.com/chemcalc/chemcalc.html

Here is a link to DIY recipes for ca, ALK and Mag. An inexpensive way to make dosing solutions.

http://www.reefkeeping.com/issues/2006-02/rhf/

I buy Calcium Carbonate in a 1 gallon size from BRS.

[Mzj7725]

Awesome Thanks

[bertoni]

You can dose the supplement into the display tank. You will want to dissolve it first, if it's a dry supplement. I dosed into the display tank regularly, especially on systems that didn't have a sump. The display tank usually is the large volume of water, and it should have good flow, so it's ideal for supplements like calcium and alkalinity that can cause precipitation.