Phosphate reduction- phos-gard vs GFO...
I use a filter sock on the output to be sure no fines enter the water, but I have used it for years with tangs and sensitive corals with no issues.
Most reactors will work with the stuff. You want a very light tumble where you are seeing just a few grains dancing on the surface of the product. It has a protective coating to reduce grinding, but don't put it to the test, just keep it gentle.
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