Replace calcium as needed, keep your KH levels up, and feed your fish and corals foods that they want and need.
On most aquariums I personally will use whatever calcium additive I think is best for that system i.e.
B-Ionic, Tropic Marin's BioCalcium, Kalkwasser or a Calcium Reactor, then feed the fish heavily and finer foods for corals and DT's Phytoplankton.
Most additives are designed and marketed on the "if you build it; they will come" mantra.
Someone somewhere writes an article or posts an anecdotal observation that after adding X to his tank he
saw improvement Y. For whatever reason people in this hobby are always looking for the miracle additive and thus companies are always looking to exploit that tendency. The problem 99.99% of the time the observation is pure coincidence and/or has no real scientific data to back it up.
Iodine and Xenia is the perfect example, someone, I forget who, said that their Xenia growth improved with additions of Iodine. That got twisted into Xenia=must have Iodine. In reality there are just as many, if not more, people who have success with Xenia without dosing I2 as those who do.
If you learn anything, learn that there are no real absolutes in this hobby. In almost every thread on this board, if a trend is almost 100% going one way, some knucklehead will have to post "but it works for me!"
With anything in this hobby, look for trends, don't take anyone's word as gospel(especially a product label!), think things through - look for a chemical reason to add something (don't add unless you can test for it and determine a deficiency), an be wary of falling into the FPE trap.
FPE = Financial Placebo Effect - your percieved success with any product is directly proportional to the amount of money you spent on it.
