Hi, i've been using carbon since day one, my tank has been up for over eight years, with all the chemical warfare going on in the tank it can't hurt, my cal stays at 450 my dkh stays at 12 and my mag is fine, here's a shot of my tank.------------My Lagoon
Carbon must be changed frequently. after a couple weeks the bacteria coats the surfaces and the effective use of it is reduced to a biological filter. The good it does probably outweighs any negative aspects. Water changes can replenish any missing elements. Be careful about adding addatives. The carbon will take most of them out and it probably is not a good idea to overdose to compensate.
I run carbon about 10 days a month (when I don't run ozone). I haven't tested for trace elements but I've been using it that way since '95 and everything seems to be doing well. I perform water changes once a month.
Some marine aquarists worry that activated carbon depletes the aquarium of â€œtrace elementsâ€. While carbon has the potential to sorb certain metals considered trace elements in seawater, several factors must be considered. Activated carbon has a much greater affinity for organic compounds than metals. Foam fractioners (protein skimmers) and ozone â€œremoveâ€ substantial quantities of trace elements as does the metabolism of all the specimens in the aquarium. The benefits of activated carbon filtration, protein skimmers, and ozone far outweigh the possibility of trace element removal. There are many trace element additives available that replenish the â€œEssential elementsâ€ removed by algae, fish, and invertebrates as well as the filtration equipment necessary to maintain these specimens in captivity.