Calcium/Magnesium Readings

Invest in a glass floating hydrometer. These seem to be the most accurate. Refractometers need to be calibrated regularly, so when you buy one get some standards to calibrate it with.

 

Ok so I got my refractometer. Calibrated it with the suggested distilled water. I took my reading and it is at 1.027. I'm guessing it needs to be lowered to 1.025 before I can get a better calcium/magnesium reading?

 

You need to calibrate it with a seawater calibration fluid to 1.0265. calibrating with distilled water to 0 has been shown to be inaccurate at reef salinities. They are just too far apart. Randy Holmes Farley had an article about it a long time ago.

 

Thank You. I will look this up. I'm guessing it shouldnt be too hard to find.

 

Why are you dosing, were they low?

 

Well, I thought they were low which is why I couldnt get a reading. After adding more reagent I discovered that the tests changed to the color that they were supposed to be. After that I haven't dosed anything.

 

Are you doing WC's with a good salt mix? Unless you have alot of corals, etc, you shouldn't need to dose with fairly regular WC's.