And to clarify, carbon 'adsorbs' not 'absorbs' what it takes in. The dissolved organic compounds it removes from the water column 'sticks' to the outside of the carbon's surface (aDsorbs). What makes one carbon better over another product is the amount of surface area that stuff can adsorb to. The process of making it (high heat in the 900s and low O2 to keep it from burning) creates many tiny holes/tunnels into the carbon itself. The more surface area on each tiny particle of carbon, the more 'stuff' can adsorb to it. Fascinating how it all works. I've never used carbon except to remove tannins or medication (and not salt, as someone had mentioned it may do). But, no harm in doing so one way or the other, it seems.
A new question; how much of the stuff in a fish shop is mainly hyped up to get fishkeepers to buy it and is of little practical use??
I've only bought dechlorinator (a necessary evil since the water I use - city tap water- has had chlorine or chlroramine added to it that is deadly to fish) and plant fertilzers. I seldom use the fertilzers as the fish produce the waste products that the plants need. If I see a deficiency in a plant, I dose for what that plant is missing. There are tons of websites available that show how to determine plant nutrition deficiencies.
I have often been in a big chain pet store that offers a 'fish guarantee' for a few days or weeks. They say that you must bring back the dead fish and a water sample. In EVERY instance, they will test the water with the dip-strips and come to the conclusion that 'something' is off in the water and that they need to buy a 'pH-adjustor ' product, a 'stabilizer' or 'water clarifying' product.
So they bag up a new guppy/molly/tetra etc. for the customer and the product they 'need.' The customer feels happy because their $1 or $2 fish was replaced for free, and purchase the extra product they 'need' for $6 or $7.
Me thinks its all about the $$$ in some cases.
I went into a store that was a 'mom/pop' kind of store once when I lived in Arizona. I told the sales person that i had a 20gallon long heavily planted fishless tank and wanted to add some plant-friendly fish to it. I said that I had never kept fish before, just plants, so needed some advice on what to buy. He 'recommended' a shoal of 5 bala sharks, a common pleco, and 3 apple snails as my 'clean up' crew, then several different options of small tetras for a shoal of mid-dwellers, with a gourami AND a male betta for a top-level fish.
Needless to say, I chose to leave and find another store to deal with. They had nice looking, healthy fish, and a good selection, but I had no trust in them.
