Low magnesium

[leetdood]

HI guys,

Ive been out of the hobby for a while and recently got back in.. On my old tanks, i never had a problem with any chemistry, nothing died, no issues over 2years.

with the new tank(has been setup over 2months now, live rock,live sand)i've had a steady decline in magnesium.
Salt=reef crystals blue bucket
mag addition=salifert liquid.

I've been told by my LFS that the sand, being new, will act as a sponge, sucking out the mag from the water, then at some point in the future , release it back into the tank showing elevated levels.. is this information correct?

tony.

 

[kharmaguru]

HI guys,

Ive been out of the hobby for a while and recently got back in.. On my old tanks, i never had a problem with any chemistry, nothing died, no issues over 2years.

with the new tank(has been setup over 2months now, live rock,live sand)i've had a steady decline in magnesium.
Salt=reef crystals blue bucket
mag addition=salifert liquid.

I've been told by my LFS that the sand, being new, will act as a sponge, sucking out the mag from the water, then at some point in the future , release it back into the tank showing elevated levels.. is this information correct?

tony.

Never heard that one before. What is the magnesium level of fresh mixed saltwater and what are you keeping your salinity at?

Coraline consumes a lot of magnesium. If you have mangroves they also consume magnesium.

 

[leetdood]

1350 from the fresh rodi salt mix. Salinity at 1.026.
not a lot of coraline as yet, no mangroves.

 

[leetdood]

so a few more checks, and thinking "it cant be the test kits"(salifert/ntlabs), i purchased a redsea pro kit.. and got the same results.. low magnesium. Someone suggested i test the salt mix, and to my suprise, low magnesium.. so a shake of the bucket, a roll around the garage floor, an empty of the bag to unsettle the settled salt and mix it back up again, (apparently magnesium is heavier than the other elemets in salt, and i'm still under 780 on all the test kits on a fresh mix of salt. (temp 24,roDi water 8tdi,salinity 35ppm) redsea coral pro salt. I've put a support ticket onto Redsea to see what they come up with.
The weird thing about it though,(2 different buckets of salt) on their website you can look up the batch number of the salt and get an analysis of the salt batch sent to your email.. and the readings on this report all give the correct readings at that time. i may try another brand of salt.. but i'll wait until i get some news back from redsea.

 

[kharmaguru]

so a few more checks, and thinking "it cant be the test kits"(salifert/ntlabs), i purchased a redsea pro kit.. and got the same results.. low magnesium. Someone suggested i test the salt mix, and to my suprise, low magnesium.. so a shake of the bucket, a roll around the garage floor, an empty of the bag to unsettle the settled salt and mix it back up again, (apparently magnesium is heavier than the other elemets in salt, and i'm still under 780 on all the test kits on a fresh mix of salt. (temp 24,roDi water 8tdi,salinity 35ppm) redsea coral pro salt. I've put a support ticket onto Redsea to see what they come up with.
The weird thing about it though,(2 different buckets of salt) on their website you can look up the batch number of the salt and get an analysis of the salt batch sent to your email.. and the readings on this report all give the correct readings at that time. i may try another brand of salt.. but i'll wait until i get some news back from redsea.

I use Coral Pro (black bucket) as well. I like high magnesium (1500) so I add it to my top off reservoir but have never measured the salt mix fresh. My batch numbers are always blank and I'm on about my 5th bucket.

 

[leetdood]

I use Coral Pro (black bucket) as well. I like high magnesium (1500) so I add it to my top off reservoir but have never measured the salt mix fresh. My batch numbers are always blank and I'm on about my 5th bucket.

the batch number is on the underside of the lid. ;-)

 

[kharmaguru]

Ha! Thanks! This last bucket is making the brown sludge in my mixing barrel (which I'm not thrilled about) so now I have something to reference.

 

[Timfish]

Biology is messing wiht literally everything in reefs systems and we're a long way from understanding everything that's going on. A good example is calcium and magnesium. Reefers know about araganoite and it's fairly constant ratio of calcium and magnesium but few are aware calcite and vaderite are also being made with differing ratios of calcium and magnesium (coraline algae typically makes calcite for example). Biofilms and endoliths are also significantly altering the sorbtion properties of substrates. The best we can do is test what we can test for and be ready to add what we can add and do water changes to remove what can't be removed with other filtering methods.