Mg Concern - Pics Included

Stand_Alone

Stand_Alone

New member
I'm seeking advice on this matter. My tank is about 4 months old with mainly SPS. I've been stable with calcium at around 400-450, alk at 8 to 8.5 but my mag has hovered around 1100 - 1200. Here is a snapshot of today's tests:

Salt mix - Red Sea Coral Pro Salt
Temp - 75.5
SG - 1.025
PH - 8.14
CA - 450
Alk - 8.5
Mg - 1100

I've been doing roughly 1-2 week 20% water changes. I've never dosed (which is odd, since I'd think by now the salt mix alone couldn't keep up with the tank's demands). I'm ready to dose but CA/Alk remain constant...

My corals are growing at a good rate. They look healthy. They could color up more but it's going in the right direction.

My question is - should I do something about the low mg?



FTS.jpg


Ice%2520Fire%2520Echinata.jpg


Purple%2520SPS.jpg


Tri%2520Color%2520Valida.jpg


Frogspawn.jpg
 
I would gradually raise it around 150-200mg/L over a coarse of 1 week.It isn't really a dangerous level of magnesium, but I would try to keep it at 1350-1400mg/L.I run mine at 1400mg/L.
 
This article may be useful if you haven't already come across it.

http://www.advancedaquarist.com/2003/10/chemistry

Randy recommends targeting 1250-1350ppm. I think this is a good starting place for most.

Be sure that your 1100ppm results are repeatable with other test kits before making any big changes, especially if you are happy with how your corals are growing/looking.

That's a little P. ventralis right? It looks great.
 
how is it your salinity is 1.025 but your alk is so low at 8 dkh? the red sea pro is suppose to yield 12dkh at that salinity and lately this batch i bought was reading 13.8dkh which I caught and didn't use or it would have given me an alk swing my sps might not have liked and your doing water changes with this salt and maintaining 8dkh?
 
Red sea pro is supposed to mix with a higher mag level than what you are seeing in your test results. And I see nothing in your system that would indicate a high rate of Mg consumption. My guess is testing error somewhere. Either in your Mg test or your salinity
 
klepto said:
This article may be useful if you haven't already come across it.

http://www.advancedaquarist.com/2003/10/chemistry

Randy recommends targeting 1250-1350ppm. I think this is a good starting place for most.

Be sure that your 1100ppm results are repeatable with other test kits before making any big changes, especially if you are happy with how your corals are growing/looking.

That's a little P. ventralis right? It looks great.
Click to expand...

I think that's the best advice at this moment. I'm using Elos test kits and they're pretty easy to use. I can repeat the same readings but I think trying to repeat the same readings with another brand is the way to go.

Yes, it's a small female Ventralis.

RickMartin said:
Red sea pro is supposed to mix with a higher mag level than what you are seeing in your test results. And I see nothing in your system that would indicate a high rate of Mg consumption. My guess is testing error somewhere. Either in your Mg test or your salinity
Click to expand...

It's been bothering me for a while why I can't get the same results as the label on the salt mix when freshly mixed. I'll see what it reads after I order some new test kits.


Do you guys recommend Salifert?
 
could your alk/calc testkit is off and testing low?
I dont know how you could be doing 20% WCs biweekly with 12-13 dkh water and then having the alk maintain at 8 dkh. Somethings amiss here. Replacing tank water with 4-5 dkh higher water would increase the dkh (prolly to 9.5 or so). Do you test right before the water change? Spiking the alk from a 20% WC can cause issues but you seem to have none. very Perplexing. Try testing before and then after the WCs and test the WC water itself. see whats going exactly. Also Id take a sample of the tank water to a LFS to get tested against other test kits. See how reliable they are. I know you dont have a lot in there to draw alk/calc but it should reduce somewhat.

honestly my course of action would be to verify all testkits and see whats going into the tank. Then raise Mag with a product like Kent M and begin to dose and see how the tank reacts. I would start dosing at a reduced level but dose none the less.
 
User error is a possibility as is kit errors with elos mg IME.Do they still use a .75 multiplication factor for mg.I have not played with there kits in a few years but I was not impressed back then.The results were not very repeatable and off by 100 plus ppm when tested with a ref sample.The salifert mg kits (as of lately)were very close to ref samples so I would like to see what you get on a new salifert mg kit before making any sudden changes.Your acros look very happy and I suspect your #s are better then your test results may be showing
 
Buy a new Mag test kit , i had same problem , my mag always around 1100, corals looking good and growed , I did water change and double dosing , but nothing change so i declined buy a new mag test kit, the fist test showing 1400 and the second time same , so I go back to old one and test mag still reading 1100 :)
 
IF and this is a big IF your mag really is that low. I would just dose it all over the course of a couple days. You can jump up on mag without any issues. I'd shoot for 1350-1400.

Oh, and I didn't like the ELOS mag kit at all. I have one I bought it looked at the instructions, and put it away.. Should just toss it at this point.
 
I think if the corals are fine at that level just leave it be... some tanks have issues keeping alk high or mg high whatever it is but the corals will still do just fine...
 
Hey guys,
I have the exact same params as his tank and I'm using Red Sea Pro as well. The salt mix is supposed to have high numbers, but I come out with the same readings as StanAlone.
 
murphreef145 said:
I think if the corals are fine at that level just leave it be... some tanks have issues keeping alk high or mg high whatever it is but the corals will still do just fine...
Click to expand...

I used to agree with this, but I find the numbers can some times be a precursor to looming disaster. Sometimes it takes a little while for corals to react and then you are left wondering why that coral suddenly RTN'd. Granted stability is often times more important then where they numbers are but I think if you can get stable even on the "low side" it's better then being out of range.
 
rigleautomotive said:
User error is a possibility as is kit errors with elos mg IME.Do they still use a .75 multiplication factor for mg.I have not played with there kits in a few years but I was not impressed back then.The results were not very repeatable and off by 100 plus ppm when tested with a ref sample.The salifert mg kits (as of lately)were very close to ref samples so I would like to see what you get on a new salifert mg kit before making any sudden changes.Your acros look very happy and I suspect your #s are better then your test results may be showing
Click to expand...

Dan - the multiple is 50 now. I am glad you think the acros look happy. This is my first saltwater tank so I'm still learning. I thought they looked ok but didn't want to be presumptuous.

Anyways, I borrowed my friend's Elos MG test kit to see what it read. Two tests showed mg at 1150 and 1200.

I'm beginning to doubt the advertised parameters of Red Sea Coral Pro.

We'll see, I have the Salifert kits coming soon.

Thanks for the advice everyone. I'll consider very carefully.
 
mix a batch of redsea pro and test. see if your batch matches their "lab tested" results.
 
Last edited:
You must log in or register to reply here.

Similar threads

D
Corals slowly dying / getting white spots water tests good
Replies
18
Views
811
griss
griss
J
Old salt mix vs old salty reefer
Replies
3
Views
711
Jposch
J
R
How to simplify my dosing?
Replies
1
Views
761
Vinny Kreyling
Vinny Kreyling
E
Experience with large colonies
Replies
4
Views
516
Timfish
Timfish
Mr31415
Low alk on new tank
2
Replies
29
Views
2K
Mr31415
Mr31415
Back
Top