Magnesium Level/Salifert Test Kit

you're OK on the salifert kit, I try to keep my Mg at 1350 but one time I raised it with BRS then had to fill up the tank with fresh RC which boosted Mg up to about 1575. I had to go thru the entire syringe, then fill it again and figure out where the level was based on how much I added.

As for the reading and bubble in the syringe, you go by the tick marks on the syringe. The air sucked in is equivalent to the air inside the tip before to draw in the solution, so you draw in 1 mL and with the rubber stopper at the 1 mL mark you have 1mL of reagent.

I've read that Mg > 1500 is good for killing off Bryopsis also. Mg will come down on it's own, I wouldn't worry about it, but I don't know if there's a maximum level or any kind of precipitate issue with relation to high Mg levels and Alk/Cal dosing.

 

Yeah I'm with you on the color change over for the Salifert Mg kit. It is not as clear cut as Alk or Cal. What i find helpful is that after adding the 4 drops of reagent #1, mix it for about 2x as long. Same goes for after adding #2. then if yo uknow from a prior test what it was at, add about 80% of #3 to that prior level rather quickly, then do one drop at a time and watch for the change over from purple/magenta to the grey/blue or rather not as purple, then make sure you swirl this for about 10 seconds, stopping a couple times to look at it (and set it on a piece of paper of something white in good light). Note the level on the syringe and check the chart for the Mg level that corresponds. Then go one drop at a time and try to look for the definitive grey or blue change over, stirring thoroughly and noting the level after each drop. It's one of those test that you have to run about 4 or 5 times until you get used to it. I have noticed that if you get dark purple after adding #2 it's harder to see the changeover. I'm not sure what causes that, but if it's a lighter purple, it's a lot easier to see the difference.