HELP...Mg will not rise.

[av8soulfly]

20 month old 100 gal cube with asst' zoas, mushrooms, monti caps, clove polyps, long spine urchin, fire shrimp, 7 fish.
Monti caps showing stress, lossed torch and some cloves, flower pot stressed, urchin dropping a few spines.
Been dealing with precipitation issues in sump.
Dosing Bionic CA and ALK 50ml daily. CA is dosed in the AM and ALK is dosed in the PM twelve hours apart.
Checked the Mg and there was NO READING on two different test kits (Salifert and Red Sea Pro).
Got a bucket of Sea Chem Reef Advantage Magnesium and added 100ml and waited 1 hour and retested. No reading...I'm talking ZERO MAGNESIUM, not just low, but zero.
Dosed additional 250 ml dry into the filter sock waited an hour, still no reading.
Dosed 1250 ml dry into filter sock, waited an hour, still no reading.
Dosed another 1250 ml dry into the sock, waited an hour and still no reading.
All Mg was dosed over a period of 14 hours.
My SG has gone up to 1.030 but still showing zero Mg.
Thinking the test kits must be bad, (the Salifert is brand new) I tested fresh sea water Mg is at 1050 using Red Sea Coral Pro salt and RODI water with SG at 1.026.
Current parameters are as follows:

CA 400
KH 8.0
ALK 2.85
pH 7.7
NO2 0
NO3 2
PO4 0
SG 1.030
Mg no reading on Salifert test and Red Sea Pro test
TEMP 77 F

I can't understand what is going on here. Any ideas? Going to LFS with water sample to seek knowledge.

 

[Rakie]

If MG is low and won't raise even with dosing, your salinity is wrong. You need to recalibrate with a new solution and make sure it's accurate -- it's probably not accurate. I had this problem, I was foolish and didn't restock my refractometer calibration fluid, thinking it would be fine for awhile -- it wasn't.

Also, make sure to properly clean your testing equipment with RODI, and rinse the vials with the water you will test (tank water) before use. This is critical.. A little spot or two can change the entire test. Shake everything for awhile, I hit it on my palm while shaking to make sure nothing settles (with some tests this happens -- Salifert isn't typically one of them, but if some can, then why not).

There's a chance both tests are fouled. Super unlikely. But possible.

 

[MnFish1]

There has to be a problem with the TESTS. There is no way Mg can be zero. If it was a problem with salinity, the magnesium would be higher not lower (because to get the higher salinity you would have had to add too much salt mix. I would recommend 2 things - first take some of your tank water, Maybe a gallon. Add Mg from your solution - and test it then. second - Make sure you're doing the tests correctly. No offense meant here - its just impossible to have zero Mg - unless you have a salt mix with a defect (i.e no Mg added).

FWIW - you could also mix up 5 gallons of your salt mix - and test the Mg in that.

 

[av8soulfly]

LFS stated that my Mg is actually too high. It took 1.5 ml of the titrant to change the color in the vial.
My stupid brain was thinking that since I couldn't get the color to change, I had a zero reading of Mg.
Now it's time for a water change to dilute some of the Mg out.
Also suggested to switch to blue bucket of Red Sea from the black bucket I've been using.
Thanks for your input people...and your patience in dealing with my backward thinking.
At least I learned a thing or two.