magnesium?

[theskunk]

so here is my question: im making a 55gal batch of mag supplement tomorrow using the 7 1/4 to 3/4 formula which is supposed to make the supplement at 47,000ppm so how much is safe to add daily? i have 2350gal with a very low mag reading 720 according to the chem calculator i need to add 31.5 gal to raise to 1350 but i know i cant add it all in one day Boomer help me out!!!!

 

[tatuvaaj]

Are you absolutely, 100% sure that you have such a low Mg++ concentration? It would extremely rare value...

In any case, if the magnesium is really that low you must have been using a very bad quality salt mix and thus I suspect that many other elements are also out of balance. It would be difficult to manufacture a salt mix with such a low magnesium content and still claim it resembles seawater

I would do a series of large water changes (for example 3 x 30%) with high quality salt mix to get a clean start. I understand it will be much more expensive but I honestly would not try to "fix" such a huge error in magnesium with additives.

 

[BigAl07]

I'm gonna have to agree with tatuvaaj here. That's a very low number. I'm not saying it's impossible but I've never seen anyone with #'s that low in a Reef tank.

Any chance you can have the water tested somewhere else or with a different test kit and tester (no offense but it could be a tester error).

With that MUCH water volume I can see where a 30% water change would be PAINFUL!

 

[BobBursek]

I agrree with Big Al, what salt are you using? I would get the water tested and if that low, I would do water changes with RC salt which has high #'s in Ca, Alk, and Mg.

 

[Boomer]

Help would be to retest that Mg++ or get a new test kit It can't test that low.

 

[theskunk]

i am positive it is that low i have never added mg i tested twice today and was able to raise the mg 100ppm by adding 5g of diy mg supplement so now im up to 820ppm

see this is a series of tubs and tanks at a lfs it is my coral system

the system tests at
sg 1.024
ca 450
alk 3.43

i dose a two part via liter meter

 

[theskunk]

i was shocked when i found that it was that low. i have had some real problems with this system not doing well lately and am currently working on a 1000g water change reservoir consisting of 4 250g barrels which should be done by the end of next week

the salt we use is crystal sea which i have been very happy with for years
i think the problem lies with lack of water changes

 

[Boomer]

Ok skunk but do not raise it more than 100 ppm / day. Ah, Crystal Sea, it is the lowest of all salts in Mg ++ ~ 1,000 ppm.

 

[theskunk]

that could explain why its low, unfortunately i can not change salts so i am just going to have to continue to dose mg im glad i just picked up 12 50lb bags of mag flake