Lime water (CaOH or CaO + water) has help me get rid of cyno
several times. It does not alway work. If adding calcium(CaOH) you need to monitor
your pH, calcium and alkalininity. When these all are stabilized, I believe this is less optimal for cyno growth.
To prove this I would have to try to grow cyno at different pH
values and record the results or find a study on this. I have not
had the time to do this yet.
Many people believe that you should never add anything you can/will not test for in your tank. In this case it is important
for several reasons.
1. The correct calcium levels are important for coral growth.
2. Your calcium level can become supersaturated. This can lead
to it precipitating out. This will change your pH,alkalininity and
calcium levels. It will take a while to correct this.
3. Your corals like stability. Temperature, pH, chemical levels and
salinity should be stable as possible. Some change by season
but not daily/hourly.
It is not difficult to do calcium additions. Many aquarist have had success adding CaOH. Many of us are not that disiplined on testing. After a while you get used to the process and "know" what your tanks need.
I expect I will get burnt by not following my own advice on testing.
