Have you test your water for Phosphates? What are your levels? Are you running a protein skimmer on your tank?
I just ran a search on this product on Carib-Sea's website and this is what I found:
Phos-Buster? Pro?s unique patent pending formula
removes dissolved phosphates in minutes instead of
days. Safe for all reef tanks, saltwater, and
freshwater aquariums of all sorts. Each 8 oz. bottle
removes at least 1.5 ppm in up to 250 gallons of
water! No more fiddling with filter bags, or special
reactors; just dose it and forget about your phosphate
problem. Phos-Buster? Pro may be used regularly
as part of a preventative maintenance program.
Product #: 08508 (8 oz.).
I wonder what they mean by "removes dissolved phosphates?" That statement is probably misleading. What they probably mean is that it binds dissolved phosphates, allowing them to be removed by skimming or other means. Skimming would be best. It is likely that any phosphate that is bound by this product but not removed by skimming within 24 hours or so would be set free again by bacterial action. Also, if you have phosphate that is bound to your rock and sediments, it will be set free as the phosphate level in the tank is reduced by the action of these phosphate binders and skimming. So you would have to keep at it for a period of time, depending on the extent of your phosphate problem.
I doubt that the product would be harmful to anything but I really have no idea what's in it. I'm just assuming that it works like similar phosphate binders.
Another approach is to use one of the phosphate sponge products. If you choose a phosphate sponge product, be sure to choose one that is iron oxide based and NOT aluminum oxide based. The aluminum oxide (alumina) products actually release small amounts of aluminum into saltwater over time and aluminum is toxic to invertebrates, especially leathers, at rather low levels. All you have to do with these products is put some in a mesh bag and place it in your sump just as you would with carbon. This would be my preferred method for dealing with phosphate.