high Magnesium Levels

[Tospa182]

HI Everyone,
I have had a tank up for about 8 months and all is good except my mag level. I can't get it down below 1500-1550. I use a RedSea Mag test unit. The titrate one. I am using Red Sea Pro Salt mix. All other readings are ok. The Alk changes as expected and the Cal changes as expected although I thought that I should be using a little more. The tank is a 190 lt cube, mixed reef setup. Not a lot of SPS or LPS.
pH is stable @ 8.2 and Salinity is stable @ 1.026

[Aydee]

Just as a test.
Have you tried testing your magnesium after you mix up a fresh batch of salt water?
So not in the tank, but instead, mix it up and test it.

Often referred to as "Test the tester".

Dave

[Tospa182]

Just tested it and it's over 1600. Looks like this is my problem. Is Red sea known for high Mg content

[Aydee]

Red Sea Coral Pro typically has a mag of around 1500 or so.

So 1600 is quite high, however, it maybe a different batch has an odd value too.

It's not impossible for it to be approaching 1600.

1500-1550 is within 'range' of what a normal batch could hit.
Perhaps get some coralline algae growing. That'll pull your mag levels down. Otherwise, you may need to consider whether the levels are harming your tank. (If not, why change it?) If they are, possibly consider another salt. Change gradually! Sudden changes are bad.

Dave

[pommie]

Slightly off topic, but whats wrong with having high Mg levels? I thought it promoted better Coraline Algae growth?

[Aydee]

http://www.advancedaquarist.com/2003/10 ... #section-2

Probably the most relevant part is:
In addition to that used in calcification, many organisms (if not all) take up magnesium from seawater. Organisms ranging from bacteria to fish take up magnesium. In many cases, there is so much magnesium in seawater that the organisms need to spend more effort pumping back out excess magnesium than they do trying to take it up. For example:

"That the kidneys of marine fish have powerful renal mechanisms for the excretion of magnesium (Mg) from the body has been known since the early 1930s…"

However, it doesn't specify what is 'too much magnesium'.

Not enough info.
However, 1600 shouldn't be toxic.

Dave

[TbyZ]

When using the Redsea test kit the reading must be taken as soon as the colour changes even if the solution goes back to pink.

[johnact]

Test kits are plus or minus 5% putting you in range of 1550 not that high
Red Sea test kits are not that accurate try another brand also take a sample to your local store see what their reading is