Regarding the placement of carbon, I think you can use both ways. for me the problem placing the carbon on filter sock, is that sometimes I get lazy to shake it twice a day, so I prefer to use fluidizer reactor.
Also I already had this reactor before hand, so im making good use of it.
There's many different dosage for zeovit method, maybe it's best for you to start from smaller dose, and run higher week after week, based on your on going observation. If it's good enough already, then just leave it with your current dosing, please do not overdose it, I did once and it almost kills half of my coral within 2 days, take a great cautions with zeospur2, in low nutrient system it's extremely powerful, start dosing half of the recommended.
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ope this helps, and good luck with your new tank.