low magnesium

coralbeauties · Jul 11, 2015

I would like to know how a magnesium level of 980 would effect sps corals? I understand it would inhibit growth but would it cause pale coloration and possible stn? I have been experiencing stn, loss of color, and decreased p/e and am trying to figure it all out. I tested my water with a different test kit today and found my mg level to be at 980. Just trying to sort it all out.
thanks
Jeff

Greenstreet.1 · Jul 11, 2015

From what I understand that if your mag is under 1280 it will cause the other levels to be unstable so that may be the cause of your issues. What test kits are you using and what are your other levels ?

Also you may want to post this in the Randy chemistry section you will get a more info.

Diesel · Jul 12, 2015

980 isn't a perfect level to be at, might want to raise that a little.
Maybe answer a few questions and we can figure it out why this is.

Total water volume ( Please include sump, etc.)

What are your parameters? ( CA, ALK, PO4,Salinity, etc

How long has the tank been running?

What are you dosing? Dosing schedule?

Which brand of salt are you using?

What brand of test kits are you employing?

What are you using for CA/ALK supplementation?

Downbeach · Jul 12, 2015

Low Mg will cause your Ca and Alk to precipitate out of solution, making them unavailable for your animals, acceptable levels of Mg are between 1200ppm to 1400ppm. Getting a second opinion on the test/proceedure is a good idea. What is your SG? What do you use to measure it with? If its a swing arm type hydrometer, or some other device that needs calibration, it may be leading you to add too little salt mix to your make up water, which by extension will be adding too little Ca, Mg and Alk as well.

redfishbluefish · Jul 12, 2015

As suggested, have someone else or even your LFS verify the numbers. That low of mag is hard to believe with the "super" salts that we use.

If that number is verified, just to give you the heads up, the volume needed will be large. Use any number of reef calculators to determine the volume needed.

kevinsmixed90 · Jul 12, 2015

I don't think downbeach meant to say to add salt to your make up water and a second opinion would be a good idea.

coralbeauties · Jul 12, 2015

My system is I am guessing 220 gallons total. I have been using salifert test kits and a refractometer for salinity. As of yesterday I am seeing
phos .07
mag 930
n03 4ppm
ca 400
alk 9.3
salinity at 1.026
I have a 2 chamber mrc calcium reactor, and use brs supplements if I happen to get any low readings. I have recently found my refractometer being out of calibration a couple of weeks ago of which I have fixed and got my salinity back in the sweet spot. (have seen fresh stn since that issue). I found my nitrate to be low and have dosed kno3 to build it up to the 4ppm level. (Still am not seeing much algae growth on my glass) So now I am finding my mag being way low.
There has been 2 other members of our local club that has been seeing some of the same issues and we all purchased reef crystals from a group buy with one of our local stores. None of the numbers on the side of the boxes matched each other though. I have made 2 water changes using red sea, one last week and again last night. I havent noticed much difference in the corals yet but havent noticed any fresh stn since the first water change and raising the no3.
What is kindof weird is my red corals have been hurt the worst. Red planet is half gone and ssc is 90% gone. I have pulled one of the affected corals and examined it closely with a jewelers loop and do not see any pests. I am confident there are no pests. I would think with pests it would be a fairly consistent demise of each coral as attacked and I am not see that. I have several corals that are just faded out with no stn, others with both fading and stn, and my blue corals seem to be unaffected.
I have sent off a triton sample and will anxiously wait for the results in the mean time I will continue bring up my mag.
thanks
jeff

Diesel · Jul 12, 2015

You trying really hard to get to the bottom of this.
Now we have some more info we can go forward.
IMO you have to raise your MAG period.
Telling us that your salt but also from others out the GB have the same issues might indicate you have a bad bucket, it can happen.
Buy a new bucket but rom a different LFS or order online.
If I was you and you might be right to see no pest but I would dip some corals especially SPS in a Bayer dip to make sure for no pest.
Some times you just don't see them but when you dip you will see the let go of the coral.
I also would turn off your CO2 from your CaRx and let it slowly drop to below 9 till your MAG is up to level close to 1400.
How's your flow in your tank?

redfishbluefish · Jul 12, 2015

Test the MAG level in fresh made saltwater and see what you get. I'm still suspecting the test.

Randy Holmes-Farley · Jul 12, 2015

I agree the test result is suspect. It's pretty hard to get to 980 ppm magnesium unless the salinity is low (say, 27 ppt or sg = 1.020).

coralbeauties · Jul 12, 2015

I checked a fresh mix of red sea coral pro and it tested at 1200. I checked my tank water after dosing 900ml yesterday and it is testing out at 1100. I kept a sample of water that was taken at the same time i took the sample for the triton test so when those results come back I can check them against what my salifert tests show. My tank has alway not been able to grow coraline very well. (no growth now at all) I use ro/di water that is well water from a farming community. I think the highest tds I get is maybe 4 going to the tank.
thanks
jeff

Greenstreet.1 · Jul 12, 2015

What's the salinity of the fresh mix and the tank ?

coralbeauties · Jul 12, 2015

tank is at 1.026 and make up water is alittle higher at 1.029
Jeff

Downbeach · Jul 13, 2015

What fluid are you using to calibrate your refractometer? I'm still a little suspicious of your SG, since the Mg in RSCP should be mixing @ ~ 1400 - 1450 ppm @ 1.0264. Did you mix your salt mix before use? There is some evidence, although remote, that the elements can separate into their respective grain sized during shipping.

MontiFanatic402 · Jul 13, 2015

I would try and give your salt a good turn, sometimes that stuff will settle, and give you weird readings....its happened to me, and I always mix my salt up before I dump it in my ro/di water.