as to what carbon I use, I don't use it in marine (though only recently returned to marine) or in freshwater for the past 15 years or so..
I do use Macropore (purigen) as I find it does remove pigments from the water (freshwater is crystal clear with it) and it does remove nitrogenous organic, reducing the overall waste processed by your bacteria and hence resulting in lower nitrates over time (compared to the same system without it)..
Maybe I am wrong but I am not sure what Activated Carbon is meant to remove?
- organic waste true but macropore does this, doesn't leach back into the system and lasts a good amount of time and more easier to see when it expired.. I don't recharge as I don't go through it (my freshwater tanks are nano) fast enough to bother, just replace when used up..
- Metals, well using RO/DI and ASW I shouldn't have too much heavy metal in the tank and water changes should take care of it in freshwater tanks, though in northern Melbourne my water quality from the tap is rather stunning..
- Trace elements and micronutrients that I want in my tank, not so good..
Sorry to throw a spanner in the works and prepared to take a beating/flaming ;-) I just never understood using carbon when it is so unspecific in regards to what it removes?