Redox is another poorly understood measurement in the hobby. Redox is measured with an electrode, very much like pH is measured with an electrode. Just as electrode pH measurements are very much dependent on a properly functioning and calibrated electrode, true redox measurements are even more dependent on function and calibration of the electrode. Unfortunately, redox calibrators do not have the stability characteristic of pH calibrators. While accuracy and precision are dependent on electrode function, many hobbyists have the natural inclination to assume that digital read-outs are highly accurate, regardless of the condition of the electrode.

At Seachem, we get many questions from hobbyists, not all directly related to our product line. We do our best to be helpful and answer questions without bias. We do not, however, follow the crowd, so that sometimes our views may seem contrarian. Here are some of the issues that come up repeatedly.

The most frequently recommended practice for reef maintenance is the addition of limewater or calcium hydroxide solution either in a continuous drip or when replacing water of evaporation.